Okay, everyone, keep in mind that this is how i see it. This is all my opinion, not me being a jerk. Also, I don't know if anyone else has noticed, but I thought I would point it out while I was thinking of it.
The Mysterious Mare Do Well episode= unfair and incredibly mean.
Rainbow Dash is having a great moment of glory. Sure, she's being boastful, but it's not hurting any pony (in fact, it /saving/ ponies) and no one minds it. Oh, wait, her /friends/ mind it. But instead of talking about it to her and asking her to tone it down, they disguise themselves as a hero that completely outshines her, brags about 'Mare do Well' in front of her, makes fun of her ("I don't think she's all that great!" "She's great." "I didn't say that!" and other examples), doesn't say anything when Rainbow humiliates herself multiple times because of 'Mare do Well', makes her extremely jealous, and Rainbow even feels sad ("They're wrong! Then why am i all alone?"), then eventually drives her to try and reveal 'Mare do Well's' identity in front of a crowd. Why? Because something she was doing was bothering /them/. The way I see it is: they put their friends through so much trouble because they didn't like the way she was acting. Even though Rainbow shouldn't have been so boastful, they could have saved her from all of this by just walking up to her and saying, "Rainbow, you're getting a bit full of yourself. Tone it down, please.".
Also the selfishness of them ruining her moment of glory because they didn't like the way she was acting bothered me as well. All in all, this wasn't a very friendly way to teach someone a lesson.