Related:

• You know you've been hacking too long when... ...you start dreaming in Tetris and trying to rearrange the furniture so it all fits neatly against one wall.
• 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 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... ...you start doing stuff like: cc -o a.out foo.c
• You know you've been hacking too long when... ...you start typing semi-colons at the end of sentences instead of full stop
• 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 are having a bad dream (being chased by space aliens, etc.
  ) and you wake up, only to have another bad dream and realize that you are STILL dreaming, and had been dreaming you were dreaming, so you wake up again, and finally wake up once more and realize you were nested four levels deep in dreaming you were dreaming....
• 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.
• You know you've been hacking too long when... ...you wake up and desperately try to start a compiler so you can use the 15 minute waiting period to sleep some more.