Why? Seems appropriate for here:
Answer:
To "get someone's goat" is to deliberately provoke that person to an angry, ill considered response.
The expression is "to let someone (or something) get your goat." Letting someone or something "get your goat" means reacting in anger to provocation instead of keeping your temper.
http://wiki.answers.com/Q/What_is_the_meaning_of_get_your_goat
(I hate wiki)
If you think education is expensive, try ignorance.