One that comes to mind for me: "Whatever doesn't kill you makes you stronger" is not always true. Maybe even only half the time!
Are there any phrases you tend to hear and shake your head at?
Have you seen children? Empathy is one of the last things to develop. There is a specific purity of cruelty attributed to children for a reason.
Civilization is conditioned into humans as a general rule, not the other way around, and needs consistent reinforcement. Humans are eusocial, but like chimpanzees and ants where war with other "tribes" is closer to a baseline than cooperation.
