Most of the time, the stamps end up on existing ones so that no one can read it. There are some Middle Eastern and South American countries that relish in stamping on existing stamps that one cannot read anything at all. I have pages filled with black or blue stamps that are totally illegible.
There have been instances where the agent at the entry or exit got upset that there were no clear empty pages to stamp. I had to remove the paper clip to release 1 empty page for them to stamp
. In some cases, I have noticed them flip through pages for that small empty space to put their stamp. I thank them profusely for doing so. ^
I would avoid removing stickers unless you are really in a bind.