Okay, I noticed something in another thread that I thought was funny, but it's so off topic I didn't want to bring it up there, so here goes:
You know you've been programming too long when you use the addage, "hard-coded in stone". It's written in stone or hard-coded, but rarely both(though trying to think up a situation when it actually could is rather humerous as well).
Yes, I have a very, very dry sense of humor.
Anyway, if you can think of any other completions of the title sentence, please do. No copying from websites or email humorlists, though.