Often one will go out to eat at McDonalds, only for the mexican dude at the cash register to mess your order up. A McAsshole is the stupid guys at McDonalds behind the counter constantly messing peoples simple orders up.
A: Dude all I asked for was a friggin McSalad shaker and that McAsshole gave me chicken McNuggets!
B: Lets McJump him after his shift is over.
A: Good idea. In the mean time I'll go take a McShit.