What does “моё терпение лопнуло” mean in Russian?

Моё терпение лопнуло means “I’ve had enough,” and the image is a balloon: лопнуть is what a balloon or a bubble does when it bursts. Patience fills up until it pops. It’s a common, slightly dramatic way to announce you’re done: parents say it to children, bosses to staff, characters in cartoons just before they storm off.

Лопнуть turns up in other vivid phrases: лопнуть от смеха (“to burst with laughter”), чтоб ты лопнул! (an old curse, “may you burst!”). Calmer versions are у меня кончилось терпение and я больше не могу. The princess’s long-suffering servant cries всё, моё терпение лопнуло! and walks out.