I always wonder, do speedsters just run fast, or do they also think fast? Like, does their brain also process information as quickly as they run? The way I think is that Hollywood's depiction of super speed isn't necessarily about slowing or stopping time, but rather about the speedster's POV when using the power, it's how their brains process the surroundings, giving them a time window to see what is literally ahead and where to run.
After all, if you have the power to run across the globe in seconds, but you can't perceive where you're going, it's just a disastrous random teleportation ability, right? In Dash's case [The Incredibles], everything happened in real time from his perspective. The way they showed how things looked relative to his running speed was basically just the same way a normal human sees. We saw him struggle with the unexpected terrain and obstacles, and he even ran into bugs. Because just like Dash, we could barely see anything ahead at that speed during the forest chase scene.