Your Understanding Of Underage Is Underwhelming

(A coworker has failed a state alcohol compliance sting. The store manager and I pull her into the office to fire her, as per our policy.)

Me: “You sold alcohol to someone under the legal age, and because of that we have to let you go.”

Coworker: “But he looked like he was 18!”

Me: “Well, the legal age is 21…”

Coworker: “So?!”