Germans, please teach me how to deal with rude doctor’s assistants

I am having a great time living in this beautiful country but some minor things are standing in the way of total bliss - one of them being rude assistants/receptionists at doctor’s offices. Do Germans grow up learning how not to let them affect your day? Most doctors I’ve met here are friendly and open most of the time but almost all receptionists I have had the ‘pleasure’ of interacting with speak to me in short sentences (‘Termin?!’), ignore me entirely or tell me off for even being there. (This morning I was yelled at for coming to the Akutsprechstunde even though my doctor explicitly asked me to do so by email). My German level is around C1 and decent enough to get me through conversations, but I get so flustered when people are deliberately rude to me. I fully understand that working in healthcare right now is exhausting and you deal with a lot of people every day, but I just don’t understand how being rude will improve that.

What is the trick? I am too much of a people pleaser to be rude in return and I am also understanding of their situation, but these situations are making me dread doctor’s appointments at this point.