Growing up, I hated my full first name. I really did grow into it until I was much older, and even then I pretty much only use it on official documents and such. In fact, there's only one childhood friend who calls me by my real first name, and even then, she's the only one that could get away with it.
I've always been Katie to most people, and it's the name that I use most often. Other friends throughout my life, in particular Crys and other people I used to go to church with called me Kate. My uncle has called me Kate-O for as long as I can remember. My niece calls me Kitty, which is close enough, and what Amber swears is going to be my old lady name. The only name I do not like to be called is Kathy. Seriously, just don't. I think that's about it on the nickname front.
Don't forget to link up with your nicknames!