From the Firesign Theatre’s album, I Think We’re All Bozos on This Bus, Fudd’s First Law of Opposition:
If you push something hard enough, it will fall over
Fudd’s Law I’ve found to be useful at various time in the ha ha, only serious sense; less so, Teslacle’s Deviant to Fudd’s Law:
It goes in, it must come out.
which is just as true, but I haven’t had occasion to use it.