He's my BROTHER

Okay so my brother and I are really close, and he is a very touchy person. Hes 22 and I'm 19, and being close we hang out in town a lot together. Almost everyone people ask us if we are dating, and I have no idea why. It's happened for YEARS. Most of the time I have to stay on my phone or walk a ways away so people don't get confused.

Well for some reason today pissed me off.

We both went to see the new Star Wars movie and sat next to this mother. We were early so we were on our phones during the trailers, both of us texting are actual partners, and suddenly the lady goes "are you two siblings?" I go yes and she said "okay, I kinda see it" I know what she was thinking before though "why are these two on their phones on a date?!" She genuinely looked ready to bitch us out if I said no. I hate feeling awkward in public because people automatically assume if a girl is with a boy they are dating