Rarity is probably my least favorite of the mane 6, She often gets on my nerves ,But has redeemed herself some over the period of season 2 and some parts in season 1. Reasons why I don't like her. ( This is all in MY opinion, you don't have to agree)
1. She Uses her friends: Using spike to get the Ruby.
2. She Lies to her friends: She lied about her friends in Canterlot and used her pet Opal as an excuse. (And I, quite frankly can't stand liars)
4( I'm Gaben, so I can't count to 3). Her personality gets on my nerves at times.
5. She is obsessed with herself: The sonic rainboom episode ( I can't stand people like this, because they remind me of the way my sister used to be)
Other than that she's an alright character who can often make me laugh, but still not good enough to make me like her more than anyone else in the mane 6.