"Irregardless"
I know it's not a saying, just a word, but I hate when people use it. One - it's not a word. Two - if it were a word, it would be redundant. Regardless is already a negative term, so to put "ir", a negative prefix, on it, you've made it a double negative. Which makes it a positive. Which makes (the way people use the word) pointless. Three: the fact that most people who use the term "irregardless" are those people who want to appear smart, and since its a pointless, non-existing word, they look even dumber.
Stop saying it. NOW.