@matt0044  
Yes that is what Twilight should have done. Gained evidence, or at the very least, talk to Cadance. Ask her questions. Find out why she’s acting this way.
 
Twilight never once in the episode tried to talk to Cadance. Other then the first meeting, she just glared at her and talked behind her back.
 
And then, why didn’t she go and ask Celestia about Cadance. I’m sure Celestia would have some answers as to why her foal-sitter was so different.
 
For a character so caught up in science, she doesn’t do the most rational things.

A friend of mine also had this to say:
 
“It’s not that they forgot about “Lesson Zero”, hell that lesson doesn’t even apply here, what applies to the Canterlot Wedding 2 parter was “trusting your gut instinct”. Sadly though, in trusting her gut instinct, Twilight rushed into a situation without enough evidence. Sure, trusting your gut instinct can be a good thing, but without proper support, it’s hard to make the claim Twilight made without more evidence.”

@SemiJuggao  
And that last part is where I must disagree. From Part 4 of my journal on ACW:
 
“This seems jarring at first, I’m sure, with the Mane Five brush off Twilight’s concerns when Lesson Zero proved that it can lead to disaster. The difference here is that Twilight isn’t not all cuckoo-for-cocoa-puffs like when she was “tardy” but just frustrated and if not for her later discovery, she’d get over it with time. It’d be absurd to expect them to be all like, “Sure, Twilight we believe you with no questions asked. There may not be evidence to prove this but you’re our friend and that’s all the proof we need.” In addition, they actually DID listen to Twilight’s claims and were concerned for her while trying to comfort her but they felt like she was just frustrated by her unfriendly reunion with her brother and jealous of Cadence for stealing him away (not helped by Chrysalis’s performance).
 
Given how it can be stereotypical of brides to be bitchy and stressed on the most important day of their lives (said day is under threat by an unknown force), it wouldn’t be such a stretch that the Mane 5 saw Cadence just being that and not the queen of a race of shape-shifting succubae. Even Pinkie Pie wouldn’t have come to that conclusion.
 
That and they were busy helping with the wedding which was a big thing at the time. I’m sure I don’t need to spell things out any further. I hope…”

@SemiJuggao  
Or at the very least, a rebellion against Celestia and Shining Armor ala the Post Nuptials fanfic series.

@matt0044  
Believe me, I have no arguments with you, and you did make a really good point. I even read your journal, and I agree with your points about Twilight’s own negative behavior. Sure, Twilight’s friends were sore at her for what she did at the rehearsal, which I understand. Because, let’s be honest, she really didn’t think things through, when she decided to just barge in and spout wild accusations without solid proof. Basically, she only succeeded in sounding like a petty jerkass.
 
However, even BEFORE the rehearsal, Twilight’s friends tossed her aside for somepony they had never even met! They dismissed her complaints about Not-Cadance being a total bitch as premarital stress, and felt that Twilignt was just being possessive of her brother! It completely betrays what they learned in Lesson Zero, and it’s also why I felt that Twilight deserved an even bigger apology!

@SemiJuggao  
I’m not going to say that you didn’t make a fair argument or a well-structured one because you did. But I feel things like what you said are kinda… blown out of proportion. I always saw it as Twilight understanding why the others didn’t believe her and chewed her out at the time and forgiving them.
 
For a better counter-arguement from me, see this journal I made: http://matt0044.deviantart.com/journal/In-Defense-of-A-Canterlot-Wedding-Part-3-362084371
 
The comments below it also make good cases.

@Psyga315  
Well, most of ’em, anyway. *shrugs

So I think the basic gist of the comments here are:
 

@James Rye  
Please, it’s not your compliments are gonna make me happy! Damn jerk!  

 
Seriously though, I’m not really much of a writer, but thank you.

@SemiJuggao
 
Awesome! You should become a writer for MLP S5! :D

@SemiJuggao  
I also thought that, but with more of him regretting it even after the wedding is over…
 
I think he’s a favorite when it comes to just making ponies break.

@Evowizard25
 
@Psyga315  
LOL Thanks, guys! As for Shining Armor, even though I’m not as hard on him as I am on the others, I would be lying if I said that he shouldn’t apologize. Hell, according to my head-canon, as he went to ‘comfort his bride,’ as he put it, he probably had time to calm down and start kicking himself for what he said to Twilight. However, before he could try and find her to make things right, I imagine Not-Cadance zapping him with an extra-strength brainwashing spell, telling him that the ONLY thing he should worry about is marrying her. It would definitely explain why he became a mindless zombie, and why he asks if the wedding was over, after Princess Cadance broke the spell.

@SemiJuggao  

@SemiJuggao  
 
That’s all good points and I admit all that was going through my head.  
You’d think Celestia would have had more patience in her student and actually stayed behind, comforted her, and then made her apologize. Yeah, to the ‘not’ Cadance, but it would have been better.  
{Actually, that’s what Shining Armor should have done…Sorry, still harping on him.}
 
And more often then not for the need of plot, past morals are thrown aside. Lesson Zero’s very lesson could have saved Equestria.
 
As well as Chrysalis….I’ve always thought she wasn’t good at subterfuge. She definitely wouldn’t make a good actress.

@Psyga315  
Gladly, here is my highly-detailed breakdown of why Princess Celestia should have worded her praise differently.
 
Copied and pasted from DeviantArt
 
“Oh, thank GOD I’m not the only one who thought Princess Celestia’s words of commendation were half-assed! This is something that has bugged me ever since I watched the episode the first time! I’m going to offer my own analysis and critique of Celestia’s poor choice of words.
 
I apologize in advance for the following wall-of-text.
 
“This is your victory as much as it is theirs…”
 
…Hmm, this is true. After all that Shining Armor and Princess Cadance suffered before they could tie the knot, it was their love for each other that ultimately won the day and allowed them to finally get married. On top of that, it was because of Twilight Sparkle that they could even do those things! Hell, Shining and Cadance got wedding bands, Twilight should get a freaking medal! Please, continue, your majesty…
 
“…You persisted in the face of doubt…”
 
WHOA, WHOA, WHOA, TIME OUT!
 
This line right here, it totally destroys all credibility in what Celestia says! Here is a list of what Twilight SUPPOSEDLY persisted against……
 

@EvilTon  
But I put more hate on Shining Armor, because it’s kind of personal. I’m a big brother and never NEVER would I be that harsh to my little sister.

@EvilTon  
Yeah, they really didn’t learn anything from Lesson Zero. {It was nice of Applejack to apologize though….She was the only one to do so…onscreen that is.)

@SemiJuggao  
I’d love to see it.

All Shining knew was that Twilight was accusing “Cadence” for no reason.

@SemiJuggao  
Yeah, that.

@Evowizard25  
(reviving an old argument)  
Actually, what really made me angry about that scene wasn’t even Shining berating her, Twilight basically made a bunch of accusations and insulted his bride-to-be based on little beyond assumptions. I was mad at her friends who turned their backs on her without a second thought when they knew about her suspicions and chose not to take her worries seriously. AGAIN! After the events of “Lesson Zero”. You know, the whole reason they can send letters to Celestia in the first place.
 
I did feel enough emotional investment to care about Twilight and SA’s relationship as siblings, since much of the first part was built around that.

I notice people have a lot of dislike for Shining Armor because of this infamous moment, but I tend to cut him a lot of slack. Remember, aside from Queen Chrysalis feeding on his love, she was brainwashing him on a regular basis.
 
What’s everyone else’s excuse?
 
I could have sworn that one of the valuable lessons they learned was to take their friends’ concerns seriously, even when they don’t think they have anything to worry about. Sure, there’s the fact that Twilight barged in on the wedding rehearsal, shouting accusations without proof. That certainly didn’t help her case, but that also doesn’t excuse them for constantly dismissing her concerns about the wedding!
 
Well, there is a bit of Fridge Brilliance in ACW Part 1, none of Twilight’s friends were there to see her give Shining Armor “a piece of her mind,” as she put it. Therefore, they had no idea she made peace with him, nor did they find out that Twilight had prior history with the bride-to-be! In other words, all they saw was Twilight being super-pissy about the wedding and that she was just being possessive. Still, even with all that said, that still gives them ZERO EXCUSE for ditching their FRIEND in favor of some pony they didn’t even know!
 
At least Applejack apologized on behalf of everypony else, but that still wasn’t enough! Hell, if anything REALLY pisses me off about that incident, it’s Princess Celestia’s half-assed words of praise for Twilight! I typed up an entire rant about why it was bullshit, but I’ll save it for another time.

@someguy111  
Eh, I can overlook that. She was Twilight’s ‘foalsitter’. Knowing about her wasn’t essential or really needed.

@Evowizard25  
Actuality I don’t hate Cadence either. I like her character and what her cuite mark represents. I just wish she was introduced in a different context, though.

@someguy111  
Oddly I don’t hate Cadance even though she kind of is the same. Actually, I really enjoy her and her character.
 
What I don’t like about Shining is that he’s pretty bland, introduced really late in the show {season 2 finale}, and for the death knoll, HE BAD MOUTHED HIS LITTLE SISTER AND FORBADE HER FROM COMING FROM HIS WEDDING!
 
As a guy with a little sister of my own, I would never do such a thing to her.
 
{It’s still nice to see someone with a similar opinion though.}