I just realised that my post sounded a bit like you
have to like Kurt if you've seen everything, which is not at all what I meant by the way. I just asked because I felt the same after season 1, and then radically changed my opinion - and was wondering if it could be the same for you
What I like about Kurt is that he has grown so much despite the difficult circumstances he is put in. He lost his mother, he didn't really seem to have any friends before Glee (and even his Glee friends are often of the backstabbing kind) and until he was 15/16 (?) he was afraid that his sexuality would make his father love him less, so he always tried to hide it from him. I think that the reason that he was often snarky in the first season is because he just felt so lonely - and his way of dealing with that is a 'better than you'-attitude (which I totally understand).
I didn't like it when Kurt wouldn't take no as an answer from Finn, but I think that was again Kurt being incredibly lonely and just wanting someone to love. I think you can see that by the end of season 1 he realises he was wrong there, and when Blaine comes along he deals with the situation in a way that is a lot more mature (for example, when Kurt encouraged Blaine to serenadeJeremiah even though it was breaking his heart).
I love how Kurt is strong enough to not let the bullies really get to him; he is who he is, and he doesn't change for anybody. The only time he wanted to change something about himself was when he felt he was not being the son his father had hoped for - which is another thing I really like about Kurt: his incredible relationship with Burt, and the way Kurt always wants to take care of him.
I think Kurt his made a few mistakes throughout the series, but absolutely everyone in Glee has done things that were 'wrong' (or at least very cringeworthy). I think Kurt is one of the only characters who has fundamentally changed for the better throughout the second season, and who at least has a decent reason to be making mistakes; nobody has had as much of a hard time as he has, and I think he has dealt with everything remarkably well.
Other things I like about Kurt is his wit, his intelligence, his love for Burt and Blaine, his ambition and his confidence (in season 2/3). He really is one of my favourite characters
Sorry for the essay
And please feel free to disagree! I'm really not trying to force my opinion on anyone, I just like talking about Kurt.