Who says that you need to become respectable, just because you have grey hair or creaky joints?

This list is for characters over 40 (even better if over 60) who refuse to "act their age". They might commit crimes, have ill-advised love affairs, travel to dangerous places, embarrass their children or other relatives, or otherwise don't give a crap about other people's expectations.

Must be a main character or a prominent secondary character (plays a major role, not just a mentor who appears briefly).

Immortals don't count if they look and act young!