Just returned from a conference at which I somehow managed not to hurt anyone with my laser pointer, and I picked up a couple of aphorisms from Tom Jackson, an EE professor at Penn State:
Jackson's 2nd rule of engineering (paraphrased): Don't argue with idiots; bystanders have a hard time telling the difference.
Jackson's 1st rule of engineering: Don't polish turds.
These brought to mind a couple of favorites from grad school:
Rogge's rule: When soldering, there is no such thing as too much flux.
O'Keefe's contradiction: Too much flux makes solder run like piss.
Salvino's rule: Any hose may be connected to any other hose with the appropriate hose clamp.
Gilroy's maxim: Graduate school is the process of continually lowering your expectations.
Natelson's variation: Graduate school is the process of continually increasing your cynicism.
Anyone out there got some other good ones?