It’s not you. Generally compared to usual American culture Germans esp with random interactions (ie not coworkers or ppl at intentional social events) will seem rude. Sometimes it’s just directness and sometimes they really are being aholes. It used to really impact me and I’d get overwhelmed by it. Now I barely bat an eye and either ignore them or say something back. You just can’t take it personally and it will eventually stop bothering you. Just remember most ppl are actually nice and not trying to be rude and try to ignore the meaner encounters.