When I was 16 in the mid 90s, aka the "I know everything, I'm invincible and you can't stop me" age, I got in a fight with an acquaintance while a whole bunch of us were hanging out at his house. Stupid fight, can't remember what about, but I decided fuck it, I was going home. I lived about 5 miles away, but I didn't have a car, and since it was 2am, there were no buses. I was going to walk home.
In the middle of the night, though a not-as-safe-as-it-seem neighborhood, as a tiny 16 year old girl.
So I did. I think, in hindsight, my friends either didn't believe I was going to do it, or were too startled by the sudden argument to realize what I was doing. I left the house and started hoofing it. About a mile out, the suburban housing neighborhood melted into a main street, with highway access. I started to notice a greyish minivan following me. It would follow me, pass me, turn a corner, and about 3 blocks later, it would do the same thing. I mean, really really obvious what it was doing. I crossed over to the other side of the street so I was walking the opposite of traffic flow, and thus no car could come up behind me. It kept doing it, on the other side of the street. About a mile later, there was a 24-hour Fred Meyer (west coast USA chain grocery/all-purpose store), lights bright, but parking lot emptyish. I immediately crossed the parking lot and went to head inside.
Just before I got to the doors, the minivan that had been following me, pulled up into one of the parking spots. A guy called out from the driver side and said:
"I don't want you to walk over here, just stay there and listen. I just wanted to let you know what I was doing. I saw you walking a while back, but I also saw a dark car that was following you.
A couple of times you went to turn around, or stopped, so it started following you down a parallel side street. When I saw it, I started to follow you both, just to make sure you were safe. Go inside the store, and call someone to come pick you up, please. I haven't seen the car since you headed across the lot."
He waited until I was inside the store, and then pulled away. I didn't have anyone to call, so I just let the night cashier know what was going on, and hung out with her for about an hour and a half. Then I finished the walk home. I've never forgotten the incident, or that man, whoever he was. During the walk, I never saw the dark car he mentioned, but I've always been convinced he saved my life that night.