No, that's not how it goes! Grahh!!!

[Shoeberto]

Using "Infinate" and "definate", instead of "infinite" and "definite", respectively.

I've actually seen people use "defiant" when they're trying to say "definite". I kid you not. It tears me up inside.

That's actually one of the things I say from time to time to test if people are actually listening/know how it's supposed to be and call me out on it. I also throw out "irregardless" from time to time; it's not that often I get corrected, sadly.