There was a point in my life when I wasn't like this, but life as a monkey has made me completely intolerant of:
A) Misspelled words in emails, etc.
B) When sh*t isn't justified in Word.
C) When things aren't formatted correctly and look like crap.
For instance, random people on this forum message me asking for "advice", but when they misspell words and their grammar is completely in the sh*thole, that pisses me off.