Are there really no stupid questions?

If we for instance take, as an example, someone thoroughly explaining something which is clear to 99,9999% of the earths adult population don’t you think the remaining .0001% could come up with some? I get that this community is a place to allow people to ask questions they can’t or won’t ask elsewhere but I certainly feel stupid sometimes when I ask questions while attending courses etc.

So bottom line, how do you ask questions when you feel stupid?