One thing I hate is carrying around lots of change. Small change is especially aggravating. Pennies are not from heaven. Often I try to outsmart ticket machines by putting coins-in in a special order so that I can minimize the number of coins I get back. It's not rocket science, but it keeps me busy. The other fun thing to do is to give cashiers odd amounts of change that help reduce the amount of change you get back. This is especially interesting when the cashier does not have a cash register that automatically tells them how much change to give. For example, if the total is 8.38, I might give 10.03 so I get 1 dollar, two quarters, one nickle and one dime, rather than the same with two pennies. This allows me to get rid of three pennies and avoid getting two more. You can see how this could be addictive.