Why are students so... Weird?

Yesterday I was sitting in my car after picking up some groceries after work and while I was, some kid apparently took a video of me sitting in my car while I was texting some friends for like a full minute and put it on his Instagram. And he was just laughing the whole time. And for some reason my students think it's hilarious to see me in my car... Texting and looking at Facebook? And it's not like upsetting me extremely but it's just so so weird and like mildly uncomfortable. I asked a student to explain why it's funny and he said "You look so sad." Like... That's just my normal face.