In the Schengen area, if you are a non-EU person, until recently you needed to ensure you are stamped in and out otherwise you'll run into issues with them thinking you may have overstayed.

After UK went all freedumb and left the EU this caused a lot of issues, I have a UK colleague that visited his wife's family in Poland over a Christmas, didn't get a stamp on the way back, then ran into problems a few months later as they argued he had been in Europe for months.