My first accident was nothing bad, but was where I learned in just my second year of having a license that you’re at fault if you rear-end someone even if they braked abruptly. I was in the second and worst car I ever owned, a ‘79 VW Rabbit, and rear-ended a pickup truck in heavy SF Bay Area traffic. It was just a light love tap and his truck was a beater, so no real damage, but we pulled off to the side and checked things out. The guy could see I was young (and stupid) and said since no damage, no worries, but he also schooled me about how fault works when I mentioned he had braked suddenly. Learned to maintain a healthy following distance from then on.