I was at the train terminal in Paderborn (visiting Germany) and did not see the sign that "suggested" paying to use the restroom—but the attendant did not miss

I was at the train terminal in Paderborn (visiting Germany) and did not see the sign that "suggested" paying to use the restroom—but the attendant did not miss that I didn't pay and almost assaulted me. When your German is rather limited it's sort of difficult to understand when someone is screaming at you...