[cheebacheeba]

Ok...I think the reaction was a little overboard, but I'm willing to bet the customer had it coming to some extent.
Working in fast food (in my experience) is already humiliating enough...underqualified asshole managers on a power trip, lording it over you because their life sucks and aint getting better, the corporations making you wear uniforms that seem designed to get laughed at, shifts forced upon you with little choice in the matter, shitty pay...it sucks.
Some customers seem to pick up on this, and are quite cool...about 10%. The rest are pretty much rude assholes that seem to think your life isn't bad enough without their stupid, low class fast-food eating asses condescending to you.
Probably a bad day, on a bad week, on a bad month...probably a customer blaming the employee for a mistake they themselves probably made..."you idiot, can't you do anything right? No wonder you don't have a REAL job", I'm pretty sure it'd have been along those lines...sometimes people snap...MOSTLY people make them.