i think the biggest one for me is RPM's...it is RPM no matter how you mean it.
RPM=RevolutionS- Per - Minute
RPM'S=RevolutionS- Per - MinuteS?????

its already plural people!

other than that, like, i umm, could care les how, uhh, y'all like talk and stuff, ya know, shizzle?

NY State Trooper: So what makes your car so special to have SVT all over it? Me: Er...It was made by Fords SPECIAL Vehicle Team?