Related:

• You know you've been hacking too long when... ...you start dreaming code.
• You know you've been hacking too long when... ...after days with YACC, you start to parse your conversations.
• You know you've been hacking too long when... ...you start doing stuff like THIS
  emacs a.out (an even worse version of this is "cat >a....
• You know you've been hacking too long when... ...you send E-mail and end each line with \n.
• You know you've been hacking too long when... ...you stare blankly at the screen and your fingers type "rwho" without any help from your brain.
  ...you get tired of screens full of worthless information scrolling so you alias rwho....
• You know you've been hacking too long when... ...it takes a conscious effort NOT to pronounce the 'd' at the end of common words.
• You know you've been hacking too long when... ...you start doing stuff like: cc -o a.out foo.c
• You know you've been hacking too long when... ...you order on the phone from a catalog, and start to give the operator your email address.
• You know you've been hacking too long when... ...in non-computer related situation you start thinking that whatever you are doing, it could be done more easily in a shell script.