My (adult) son and I vacation together sometimes. We might get upgraded and thus may not have seats together. I'd prefer to sit with him. We share food, drink coupons, sleep meds. We rarely talk. It's just more comfortable (for me) sitting beside someone I know. I had a flight last week and the guy next to me talked the entire flight. I'd much preferred reading, but I couldn't figure a way out. I've sat beside some really crazy people who wanted to talk about UFOs and secret cabals. I've sat beside people whose political views were offensive to me. I never ask for an unlike exchange. Sometimes people don't want to switch and that's fine with me.