Cleaning your entire plate. Like, compulsively.
As a rule, the kids of NPH Guatemala are not allowed to leave a meal without having eaten every single piece of food on their plates. It's the same philosophy that moms and dads around the world use on their own children -- "There are starving people out there who have nothing to eat. You will not waste this food."
So after months and months of eating with the kids, it starts to rub off on you. No matter where we volunteers eat these days -- in restaurants, in our own houses, on vacation -- we have such a hard time not finishing our plates.
Result: Good that we are not wasting food. Bad that we usually end up going into a food coma after eating too much. We might need to learn to start with smaller portions. :)