Heights are different.
When you look at something around you from ground level it does not seem very high. A chair, table, a roof - chance is high that you would be able to jump down from these. At least when you see them from below.
Now try to climb that chair or table. When you now see the height from above it (most likely) feels very different. The height is now much higher and that "jumping down" might seem less attractive.
The height might be the same, in meters counted - but your perception and ability to act is very different depending on your position.
Do the experiment. Climb your desk and see how high it is.