"Now THAT guy got canned!"

So now that I have an actual small salary to complain about coming my way, I can turn my attention to making the most of my final days in food service. Having decided that giving notice is for pussies, I've begun brainstorming ways to piss off some of my favorite categories of customers:

To the groups of kids that order 8 different kinds of frappucinos so that we have to actually make them all separately:
Tell them we're out, and give them directions to Coffee Bean down the street. (Actually that'll just piss off the people in Coffee Bean, but at least it'll get rid of the kids.)

To the people who ask for a particular piece of cake or something out of the pastry case:
Try it. Announce loudly that it's kind of stale.

To the people who pay for a small cup of coffee with a fifty:
Start counting out change from smallest to largest, using lots of painstaking mental arithmetic. "Let's see, that's... thirty-three ones, plus three fives is... 37, 42, 47... wait, um, like... ok, 48. Let's see, I think I'm out of quarters, but I should have enough nickels and dimes... would you like a bag for all this?"
(Bonus: remarkably efficient way to piss off large numbers of people behind them in line, too)

To the people on their cell phones:
Zone out until they're waving their arms to get attention. Say wasn't sure they were talking to me.

To the people who ask for a cup of ice water:
Hand them mine. Tell them it tastes funny.

To the asshole who thought I was gypping him on his coffee purchase:
Fill the cup all the way up to the top. Don't snap the lid on. Be all "I told you so" when he finds out the burned way why we don't do that.

To the low talkers:
Yell. Someone has to lead by example.

To the parents who subject us to their indecisive children:
Constantly question the child on whether or not they're sure they want a piece of cake. Once a definitive choice has been made, tell their parent about its nutritional content.

To the grown adults who can't make up their minds either:
Ignore them entirely and start taking orders from the people behind them in line. Try to insert a lot of playful banter so can look irritated when the person skipped interrupts to try to get served. (Hmm, may also work for cell phone talkers...)

To the grown adults who only have their minds made up until right after they've paid for their order (what did you think that process meant?!) and then decide they're not in a latte mood and would rather go for a frappucino:
One word: firebomb.