In Back O' Beyond, a mountain wall lacks proper collision and functions as a teleporter. When you drive through it and fall into Blue Hell, the game's emergency system spawns you at the nearest pedestrian path — which can be extremely far away since the area has almost no footpaths nearby.
Source: Back O' Beyond Teleporter — CC BY-SA
A plane so big, the game forgets how to kill it.
GTA: San Andreas
You can literally outrun the weather in San Andreas and break the sky itself.
GTA: San Andreas
A palm tree in GTA San Andreas is so inconveniently placed that pedestrians spawn on it and immediately fall off.
GTA: San Andreas
This prop in GTA San Andreas makes a sound almost no other decoration can
GTA: San Andreas
Saving at Madd Dogg's mansion permanently breaks every basketball court in the game
GTA: San Andreas
The satellite dish is so tall that planes constantly suicide into it—and your girlfriend will call to complain.
GTA: San Andreas