Restaurant patrons who leave lousy tips.
Customers who tend to come in large parties that seperate checks to pay the smallest individual tip. These customers usually order discounted items on the menu, use coupons, and ask for water with extra lemon and sugar to avoid paying the price.
"Do you see those cafe chickens at table 5? Everytime I ask them if they would like something, all I hear is cheap, cheap, cheap!"
"They sound just like little birds!"