8. The Chicken - M*A*S*H
Another beloved war-time sitcom from yesteryear, M*A*S*H was one of the most-watched sitcoms of all time because of its humour, but also knew how to hit the serious notes when required.
None achieve that more than this moment from the series finale Goodbye, Farewell, and Amen.
Hawkeye, being treated at a mental hospital, opens up to the doctor treating him about a time he was on a bus when the enemy suddenly surrounded them. They turned out the lights and everyone fell silent, apart from a chicken a woman was holding. He implored her to shut it up, and eventually she kills it in order to silence it.
And then he realises it wasn't a chicken at all, but a human baby, and breaks down crying. It's a devastating reveal, and a moving study of PTSD.