On the one hand, I want to start such conversations. On the other hand, I have a problem with approaching people in situations where they cannot get away. If I make the person sitting next to me on a plane uncomfortable, they can't just leave the area.
One solution is to look for signs of disinterest or discomfort and disengage from the conversation if you do. If you have trouble picking up on those things, you can always try being more passive and seeing if they pick up the slack or try to engage you further.
r/Fitness does a weekly "Moronic Monday", a judgment-free thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. I thought this seemed like a useful thing to have here - after all, the concepts discussed on LessWrong are probably at least a little harder to grasp than those of weightlifting. Plus, I have a few stupid questions of my own, so it doesn't seem unreasonable that other people might as well.