I hated the name that every one of my animals came with. They were
"Fred"- had it for five years, changed it to Argon and he never noticed
"Jonathan"- Had it for six months, but was pretty much referred to as 'puppies' at the shelter. He never knew it, so it wasn't a big deal
"Precious"- She only had it two weeks, and is a cat, but the thought of calling her that for 15+ years made me cringe. So she became Cheshire. She doesn't seem to know her name, but she's the stupidest cat I've ever met, so that might play into it.