I'll tell you what gets me stirred up. Rude, stupid people. But that's for another thread altogether.
If this kind of stuff has already been mentioned, my deepest apologies. What irks me is when people who should know better mispronounce certain words. Those words that are infuriatingly commonly mispronounced are:
Axe instead of Ask, as in "Can I axe you a question?"
Nucular instead of Nuclear, as in "We don't want to go to thermonucular war."
Supposably instead of Supposedly, as in "Supposably she carried that baby around for 12 months before she realized she was pregnant."
Expresso instead of Espresso, as in "Can I get me some milk in my Expresso?"
Pitcher instead of Picture, as in "God dammit, take my pitcher already."
Liberry instead of Library, as in "I took this book out of the Liberry back in 1976 and now I owe $3,000 in late fees."
There may be some others, but these are more common so they bother me more.