They think they can get away with anything, especially if it involves saving money. The worst example of this is the Depression-Lemonade maker. Usually they're female, between 30-60, and have a scratchy irritating voice
Other offenders include the guy who parks in two spaces in Cerritos, the lady that uses her baby as an excuse to cut in front of you in line at the grocery store, and the guy who loves the food when you ask him 3 times during dinner how everything is but when it comes time to tip the food apparently wasn't that good despite the table eating the whole lot even the piece of mint that was a garnish in the raita.