Literally, to the brink of mental instability.
1. When you call someone's office/cell phone/house/whatever and their message says something along the lines of
"Hi, you've reached redundant man, I'm currently unavailable at the moment but if you leave a message I will return your call."
CURRENTLY and AT THE MOMENT mean pretty much the same thing. I get it, you're not there. You might want to re-record that out message so that you sound a little more intelligent, and also, a little less nasal-y.
2. When someone is describing a feeling that they've been somewhere/seen someone/smelled something similar before and they say "It was deja vu all over again." Deja vu MEANS recurring again so you needn't say it twice. Also, it is annoying when you are constantly explaining your feelings/dreams/memories to your friends. They don't really care.
3. When you or someone you know is preparing for an important and necessary entrance exam to college and either you or people around you keep calling it the "SAT Test." SAT stands for Scholastic Aptitude Test. That means that you are actually saying Scholastic Aptitude Test Test. If you cannot comprehend this and correct yourself, you might want to rethink college after all.
Because I am a word nerd and a grammar nazi there are many more things of this nature that drive me nuts. I'm sure I will think of more soon but in the meantime, does anyone else get irrationally upset about things that people say incorrectly?