Burgers are definitely supposed to be held in your hands, I find that cutting it with fork and knife makes it so you can’t get all parts of the sandwich in one bite.
Back in the day, I stayed for a week in a tiny town in Belgium (called Hornu.) I loved going to this bakery every morning for their amazing fruit tarts. I'd always have a nice chat with the sweet, old owner while I was there. I liked talking with her because I could practice my French. Close to the end of the week, she asked me where my accent was from and I told her I was American. She got all excited and started trying to sell me *everything* in the shop. The last couple days I came in, she would introduce me to other patrons and tell them about me. I definitely did not expect that reaction. It was well-intentioned but pretty weird.
United Kingdom: (from the back of the room) He's my son, you jackknife wanker!
Germany: (to UK) Shut up!