Why Is Yahoo Messenger the Most Unreliable Piece of Software in the Universe?

I can honestly say I don't have any problems with Yahoo Messenger. It's the only IM program I use. It seems fine as long as you remove junk files from your computer regularly, dump invalid registry keys, clear cache, defrag, keep .Net Framework, Adobe Flash Player and Java updated Messenger works with no problems. I'm currently using version 10 and refuse to upgrade to 11 at this point because it's still Beta.