Misspent Youth
Said of oneself by a (usually older) person when they demostrate in front of unsuspecting onlookers a physical skill that belies their innocent looks or background. Such a skill usually reveals experience with a seedy, suspicious, questionable, or possibly illegal activty. Its a humorous self-deprecating confession of sorts that this skill was acquired by having practiced it in their youth; whether that's actually true or not.
Example 1: An old guy helping a stranger (who has locked their keys in their car) quickly jimmies the door open with the dexterity of a professional car thief.
Stranger: You made that look easy?
Old Guy: Misspent youth.
Example 2: A tiny old man steps up to a pool table puts his bet down then proceeds to clear the table to everyones amazement. As he pockets his winnings.
Amazed onlooker: How'd you do that?
Old Guy: Misspent youth.
Stranger: You made that look easy?
Old Guy: Misspent youth.
Example 2: A tiny old man steps up to a pool table puts his bet down then proceeds to clear the table to everyones amazement. As he pockets his winnings.
Amazed onlooker: How'd you do that?
Old Guy: Misspent youth.