If less friendly, they'll take the controller, call them a noob, and do the trick themselves. If that person's character is friendly, they'll explain the trick to someone having trouble with the game. When portrayed in other mediums, it's usually to show that someone is really good at the game. Sometimes this is acknowledged in-game due to the trick skipping items that are part of 100% Completion, but in other games skipping the level makes no difference at all.

Some players feel that this method of clearing a level isn't considered 'truly' beating it, or call it outright cheating. If a target time or score is far too good to get the conventional way, the game could be hinting that this method exists.

Tricks may include exploiting glitches or flaws. But if you Google the level, stuff will come up, namely, people claiming that they beat it in 10 minutes tops. A level that would normally take an hour to beat or high effort. But some have a really easy way to beat them. Some are hated by many people for being too damn hard. There are many types of video game levels.

Top Man watching Mega Man fly over a platforming section with Rush Jet, Mega Man issue #41

Fallout shelter delaying leveling