Hello guys. I was wondering if any of you have had this happen and if you might have some advice because I usually don't know what to say on this situation. Also some reasoning as to why people do this would be great too because I can't really figure it out.

So I live in a small University City In France. Since I am an exchange student I bump into a lot of other exchange students frequently on dates. This one time I was with a cute German girl and as we were walking back from a bar, a group of people I know but am not friends with (also exchange students) comes by and they all yell in unison:"good luck". Well this kinda made the girl freak a little. Maybe nothing would have happened but the comments certainly didn't help. Do they realize this? Or are they doing it on purpose? I'm not very attractive. I'm average at best. I have this theory that people say these things to fuck with people who they subconsciously think shouldn't be getting laid. Another time at a party I meet a cute Italian and we started making out and we headed downstairs to grab a smoke. Well,. Again a group of exchange students(not the same ones) see us coming down and they started clapping and hooting. They didn't know her but they are people that I know but wouldn't call friends. Again, Seemed the girl freaked a little. What would you say? I don't know how to reactive ever. I just stare blankly.