Reference to a couple of scenes from the movie Rain Man where Raymond points out Charlie threw his pants on the highway (that were from the wrong store) and when Raymond wants to have 8 fishsticks (not 4) on Tuesday, both a reference to the need for order and routine.
Commonly used by myself as a sign-posting of my own self awareness of my own seemingly irrational need for order and routine, and/or to illustrate how uncomfortable I am feeling at something trivial or small "not being quite right".
Example usage:
Jeff Derpington: Hey Nicola, these unit tests are failing because of some stupid error about inconsistencies in all the variable descriptions. I'm just going to add an exception because who cares about the descriptions being self-consistent right? It's not important.
Nicola: Uh oh, pants on the highway, 8 fishsticks not four. ...uh, sure, I guess so. :o)
or
Beauregard Derpington: Places mug back in the cupboard.
Nicola: Uh oh, pants on the highway, 8 fishsticks not four. ~moves the mug to a different shelf in the cupboard~