When I was little I had this problem where the seatbelt wouldn't let me breath. It would get stuck, and be really tight. This is possibly what happened with some people who don't like seatbelts. Despite this, I always insisted on wearing mine in other people's cars, and wouldn't move the car if someone wasn't wearing theirs in mine. I actually pulled into a parking lot once when a friend removed their seatbelt after we were moving.
(I only had three rules in teh car, 1. everyone wears their seatbelt. 2. No smoking. If you need a smoke, ask, and I'll find a parkinglot. 2. The driver's word is law. You can ask for the temperature to be changed, or the music to be changed, but if I say something needs to happen, it happens. There were a few complaints about any of the rules at one point, so I had to explain to them that no one was going to die in my car on my watch, that being the driver meant I had their lives in my hands, and that I can't breathe around cigarette smoke.)
In college, for the first two years, I needed to be driven around, as I did not have either license or car. The friend who drove me around the most had a heavy foot- once the car was started it was almost impossible for me to buckle. She didn't care about seatbelts, so she would go as soon as all the doors were closed. I developed the habit of buckling before my door was closed. I also developed the habit of staying buckled if I'm in the car regardless of whether or not the car is currently moving, due to many instances as a kid where I didn't realize we were about to start moving and we're already on the main road before I realize my seatbelt isn't on.
While there is a point that the one at fault is almost always never hurt, not wearing a seatbelt doesn't hurt anyone but the person not wearing the seatbelt. The reason the drunk driver survives is because he was wearing a seatbelt. (I seriously don't know anybody who doesn't put their seatbelt on when they're drunk... even if they usually don't wear one.) I will never understand the chafing against safety measures death-wish that some people have, but it is there. I have never really been comfortable with there being laws protecting people's safety. I'm okay with rules doing so (not laws, not government, but rules, personal stuff), but if people engage in unsafe behaviors, they already have consequences for those behaviors. Why should society put even more consequences to them? Society is only supposed to keep us from hurting other people, not keep us from hurting ourselves.