Well she may not stick with the lessons she has learned over the series, but she lives up to her name. I love her because she is the sweetest of the Mane 6, adorable, innocent, and many times inspirational to my own behavior. She teaches the true meaning of kindness, and is really brave when it comes to her friends. This is why I think she deserves best pony. :3

It's because she's cute.

She's boring to me, my least favorite pony

She's boring to me, my least favorite pony

Nobody is saying that everyone likes Fluttershy.    Many people are turned off by her shtick and I've carried on civilized discussions with several of them. 

Who is your favorite pony, BTW? 

Fluttershy is my least favorite pony, to be honest...

People like for one reason: She's "cute". And many will just like for that reason and will literally attack you if you honestly disagree with them. 

I see no character to her past her shyness, she is nothing more than an underdeveloped character with no interesting character features to her, she is a mary sue too. She faces her shyness, twice without help and reverts to going back to being shy, and finally, I get tired of people who love her because Gilda yelled at her.

Fluttershy is my least favorite pony, to be honest...

She's boring to me, my least favorite pony

Thank you, same here.

Yes people like Fluttershy in large part because she is cute, because of her personality it is kind of hard not to like her. Derpy is my favorite background pony in part because she is so adorable and is also one of the things that made Sweetie Belle my favorite CMC. But I don't think her being adorable is the only reason people like Fluttershy as some have suggested.

Many people especially many people who are introverted and shy understand what it is like to be afraid, and no pony has showed more fear than Fluttershy. But she has also shown a great deal of bravery by trying to overcome some of those fears which to many people makes her an interesting, relatable character and also a pretty good role model.

The fact that she is written a tad inconsistently with her learning lessons and then forgetting them a few episodes gets on my nerves too, but I still like Fluttershy despite this and still understand why so many people like her. But I guess we will see what they will do with her in season 4, what they did with Rainbow Dash and Applejack in season 3 but I may be a tad biased because I tend to like pretty much any episode that stars AJ.