yeah, there are assorted encounter types you can be interrupted by, not all are bad but many are. some start unique quests.

The encounter often times is related to where you are, so if there is a bandits hideout in the woods near a place you’re fast traveling past they might hop out and try to rob you.

Or you might run into a weird person near a village.

Or you might just run into some dudes that wanna wrestle.

These people are in the world otherwise and you could run into them while not fast traveling too, but when fast traveling you’re not like to avoid “bad” situations