I have been in three car accidents, not a single one did I wear a seat belt. I came out of all three completely unharmed, and two of those totaled my cars. My grandfather was in an accident where he rolled his car three times, his biggest injury, and his being trapped, came from his seat belt.
Now, I am a short girl and every seat belt I have ever used digs into my neck, some have drawn blood just from using them. I am terrified that I will be trapped by my seat belt when my car catches fire, I am terrified that something from the accident will make it impossible for me to get the seat belt unbuckled. Worst of all, I am terrified that my engine/debris/anything will fly through my windshield and I will have no way to move out of the way.
Given, I never wore a seat belt before due to my fear, but now that I own a 2009 Toyota Corolla, I wear it all the time, out of habit, because the damn car beeps obnoxiously if either front seat belt is unbuckled for anything over 5 mph.
P.S.
There was a man in New Hampshire, you don't have to wear a seat belt if you're over the age of 18 there, who's life was saved by not wearing a seat belt BECAUSE his engine flew through his windshield and he was able to move out of the way.
My fear may seem silly and illogical to you, but it makes perfect sense to me. I hate them, I'm scared of them, I use them anyway.