Depends on the situation. I've shrugged off most injuries -- bicycle and motorcycle crashes, sports, fighting. Heck, I was an amateur boxer until my early 20s, so getting hit and pain were just routine. You've gotta shrug it off instantly or there's no way to survive in the ring. I've seen guys quit, not because they were necessarily stunned, but you could see in their faces the pain just wasn't worth continuing another minute.
But being hit by a car almost three years ago stayed with me. Still hurts every damn day. And that sticks in my mind most rides now. There are days I'll go for a walk or run rather than get into traffic. Running hurts worse than bike riding. But nothing hurts like this daily neck, shoulder and back pain.