lose one’s marbles—(coll.) go out of one’s mind; start acting in a strange way:
- I may be old, but I haven’t lost my marbles yet.
Cf.: have all one’s marbles—(coll.) be sensible; be in one’s right mind:
- Do men who have got all their marbles go swimming in lakes with their clothes on?
pick up one’s marbles—(U.S. coll.) leave an activity one has been involved in with other people:
- If you don’t like the way we do things around here, well, you can pick up your marbles and leave.