These are far too many reasons, simply existing in the same plane of existence is enough to ship two characters.
Forget same plane, I don’t think there is any reason why one wouldn’t ship two characters.
Forget characters, there is no reason why one wouldn’t ship any two things ||
Forget two, there is no reason why one wouldn’t ship

@Exhumed Legume  

 
Spike: “You make an excellent point. Perhaps we should discuss this further more…comfortable?” >_> ^_^

SS: Hey, Spike… right?  
Spk: Yeah… you…  
SS: Silver Spoon.  
Spk: Okay.  
SS: So, I guess noticed that you and I are about the same height and general size.  
Spk: Oh okay that’s interes- WAIT! WHAT? No, don’t sa-  
SS: Sorry, but it’s already happening.  
Spk: B-B-But I didn’t even know your name like less than a minute ago.  
SS: I didn’t even know that you existed like a few days ago. But in the end that wouldn’t stop… them.  
Spk: But that’s messed up.  
SS: I know but it’s offical… we’re being ‘shipped’.  
Spk: *whimpers* is there already a na-  
SS: Yeah.  
Spk: …  
SS: Silverspike. Ugh.  
Spk: What is that? Sounds like a goatzilla sequel. Spike vs. Silverspike. Or Rainbow Dash has met her match. SilverRainbow.  
SS: *Laughs!* You’re actually pretty cool.  
Spk: Thanks, you are too.  
SS: Friends?  
Spk: Friends!  
Internet: SPIKESPOON! SilverSpike!  
Spk: I bet Princess Cadence had something to do with this.  
SS: What? Are you saying that there IS a Princess out there that ACTUALLY DOES STUFF?!  
Spk: Kinda. But Twilight does stuff too, you know.  
SS: But doesn’t she get you to do like have of that stuff.  
Spk: What n- Hey! That’s pretty true!  
SS: And the other half of the stuff is just her fixing problems?  
Spk: Well, yeah…  
SS: Problems that SHE created, to begin with?  
Spk: Well, I wouldn’t say tha-  
SS: Want It - Need It Spell.  
Spk: Okay… Mare! I never even noticed.
 
AD: I think we all wish romance was this simple in real life… well, maybe not this simple, but still.

@Yet One More Idiot  
“She can have your heart, you don’t need to love me to knock me up.”

…sorry no, my heart belongs to Ra…I mean, Sweetie Belle!
 
xD