Bart the Genius

Literally means to derail or leave the tracks. Used figuratively and commonly to describe someone, especially a young person, who has lost their way morally or behaviorally. Often used in a concerned or sympathetic tone.

Literally 'to spoil/ruin it for them'. When used about a person (especially a child), it means to spoil them through permissiveness or bad influence. Can also mean to ruin something concrete.

Literally 'to wind up' (like winding a toy or clock). Used to mean encouraging or egging someone on, usually in a way that makes things worse. Not interchangeable with plain 'encourage'.