Oh Judith - I do that too!! And add the 's' to the end of plurals (pound is often used where it should be pounds - drives me nuts!).
On top of being wound up by 'should of', would of', etc, and the misuse of apostrophes, my other hate is tautologies! For example - ATM machine (automatic teller machine machine), PIN number (personal identification number number), and the one they seem to use often in documentaries (when I really feel they should get it right!) - 'a myriad of'!!! Since 'myriad' means 'a lot of', saying 'a myriad of' means 'a a lot of of'!!!
