Don't DON'T open your window. If there is something wrong with your car, you can find out when you drive away to a service center or gas station or police station or ANYWHERE else.
I'm really sorry to the guy who was calling out to me as I walked in to the store if he really needed help, but come on! You can get help from the store. I am not stopping to talk to you. What is the worst that can happen to you? You feel bad for not helping? What is the worst that can happen if you respond, get within arms length? I dare not imagine.