@LanceOmikron  
No, there were plenty of episodes that showed Pinkie as something more complex than simply comic relief. A Friend In Deed, particularly.
 
Beyond that, though, it’s not that she was used exclusively for jokes in this episode that bothers me - it wasn’t her episode, I don’t know what else she would have been expected to contribute. What I hate, and what a lot of other people hate, is that those jokes were completely out of character. Pinkie does not act like this. She constantly strives to make everypony around her happy.
 
In Griffon the Brush-Off he specifically refused to play pranks on Fluttershy because she has enough social awareness to know Fluttershy would not be able to handle it, and yet in Filli Vanilli she did nothing but attempt to scare Fluttershy. And it should be noted that the only other episode where she’s done anything even remotely like this was Luna Eclipsed, which takes place on the one night of the year when “being scared” is considered the entire point.

@Background Pony #8C53  
“As of S3”? Wasn’t she already the comic relief from the get-go? That’s kind of her thing.

@Background Pony #E4E5  
“Hilarious”, yes, hilariously flanderized.
 
As of S3, Pinkie only exists for comic relief purposes. She’s not a character anymore, just a walking gag machine.
 
Filli Vanilli is a perfect example of this.

Pinkie, I’m not blind.
 
You don’t have a dick.
 
Don’t friggin’ taunt me…

@Turnways_Flip  
Pinkie was hilarious in that episode.

REALLY bad timing coming right after an episode where Pinkie Pie spent the episode tormenting Fluttershy for no good reason.

Ahahahaha, like hell you are.