I've covered this before, but apparently someone out there isn't reading my blog or following me on Twitter, so spread the word.

Quotation marks cannot be substituted for italicization or bolding of text!

If you wish to draw attention to a word in a document or on a sign, that is not a job for quotation marks. Rather, quotation marks imply that the word within them is not really what it says, and often is meant sarcastically. For example, there is a big difference between:

Thank you so much for all your help

and:

"Thank you" so much for all your "help"

This reminder was prompted by some signs that have popped up on corners near my house in the past week. See if you can spot the problem.There is a difference between a massage and a "massage." Your girlfriend wants you to give her a massage; I want your girlfriend to give me a "massage."

Edited to add:
My sister read this and was surprised I forgot to mention the episode of Corner Gas where Lacey offered a "free" pilates class.