I hate Subversion
I really really hate it. Every time I try to do anything USEFUL with it, like try out an idea in a new branch and then merge the bits of that branch that worked out back to my main line, it barfs all over me with totally crap-ass error messages that nobody could ever, EVER understand.
Also, despite their claims to the contrary in the documentation, svn will happily shit all over your working copy when a switch fails. So much for atomic operations.
I’ve had it. I’m switching to Mercurial.