I wish I never upgraded to 13.10. Sometimes drag-maximizing my window can crash my entire system. And compiz leaks memory like a sieve, sometimes I will wake up to find compiz using ~5.5gb of memory and the system will be unusable. Gotta restart!
When I first upgraded, I thought "oh, it's always like this at the start, they'll fix it." And here we are at the next version and it still hasn't been fixed.
Probably jumping ship (to another Linux distro) once my next work deadline passes.