Maximum Capacity Overload

Someone gets inside an elevator, expecting to be the only person there. Then suddenly, dozens of people cram themselves into the tiny car, which may or may not exceed the "maximum capacity" sign displayed on the elevator. You know where this is going by now.

It doesn't even have to be suddenly crammed for this trope to apply. It could even involve the elevator slowly filling up with passengers until it reaches its breaking point, or one extra passenger getting in a totally packed car. Either way, it's no good.

In the worst case scenario, it leads to Elevator Failure. At best, it's just an Uncomfortable Elevator Moment of a different sort.

Anime and Manga

 * In one episode of Detective Conan, the elevator gets stuck when a group of characters get in. Later, Conan gets an Eureka Moment when he remembers that he is now a kid, and thus too light for the elevator to go over capacity

Live-Action TV

 * Near the end of an episode of The Fresh Prince of Bel-Air, Will is on an elevator when dozens more people get on. He looks at the maximum capacity sign, and then begins to scream.

Newspaper Comics

 * In The Far Side, we see a man on an elevator with several elephants, and he watches in horror as one more tries to get in. The max. capacity is shown as several thousand pounds.
 * This was deliberately done in one Spy vs. Spy comic, with White tricking Black into carrying several 1000-pound weights on an elevator (he thinks they are White's secret plans).