Wouter, I also type ls (or l) as a kind of nervous habit, sometimes 4 or 5 times in a row. That's interesting. (I also type w and most annoyingly df (which sometimes hangs if an NFS server is down).)

At least that's better than biting your nails. Maybe zsh could be taught to give us a virtual rubber-band snap on the wrist when we nervously ls.