When a bee isn't pathfinding, it will fall like an iron golem instead of slowly floating down like a chicken, parrot, vex, or blaze. This causes bees to awkwardly drop out of their nest/hive instead of smoothly hovering down. It also happens to baby bees when they're born. The best way to reproduce this is to run the following command:

/summon bee ~12 ~12 ~

The bee will fall quickly instead of slowly fluttering down. Even though bees don't take fall damage, it looks painful; poor bees.