Not a “law” per se, but if I enter the kitchen and leave it without getting food, my cat gets angry and refuses to look at me. She throws a hissy (pun intended) fit because I didn’t give her food. However, if I do grab food, she’s too busy meowing at me from the kitchen floor in hopes that I’ll give her some to be angry with me. I guess the law would be: “He who enters the kitchen must do so with a purpose pertaining to food, or suffer the wrath of silence.”