I suppose I have a couple. Ones that I mainly use (or used to mainly use) I think are fine, but about 7 years ago or so, on another forum, I had a couple of names which, at the time I thought were great, but now I'm like 'What was I thinking?'
My name on this forum, which is basically the one I use when I join sites now, has pretty much become it's own thing, whereas originally it was just an abbreviation. Possibly one reason why I like it so much, and while if I joined a place now with the original name, I might regret it, this one I'm perfectly fine with, 'cause no one would really know what it means. haha