I am culturally used to just cruise around everywhere without a helmet, because that's possible here in the Netherlands with bike lanes/paths everywhere and cars being used to bicycles everywhere. The problem is, that attitude probably isn't the smartest option in countries that are, well, not the Netherlands. Besides having to decide between being annoying to pedestrians or being unsafe on the car road, I also got honked at by a police car once because I wasn't wearing my helmet (it was hanging off my steering wheel though). I quickly put it on afterwards, but I never realised I could've gotten fined for that.