Except age rating is a joke - especially 18+. I get that many games are violent, contain sex scenes, drugs etc., but in my eyes 18 is a barrier when you become responsible for your actions, which would imply playing 18+ games is dangerous like alcohol and cigarettes, while it's just a PEGI's way of saying "Somebody said fuck several times".
Like Witcher 3 obviously fits into 18+, but not because it's should be 18+, but we got used to these games being 18+. At the age of 14 in school I was required to read Sapkowski's novels, but god forbid you play Witcher 3.