For context, I am female and look way younger than I am (due to being short and having a babyface).
So, this was around 10 years back, I lived in Potsdam at that time, family and friends are in Berlin, so I was often going back. (Potsdam is a neighbouring town of Berlin.)
I'm waiting at the main station in Potsdam for the regional train to arrive, it's full, since it's friday and there's a Uni in Potsdam so a lot of students waiting, too.
I notice this guy looking at me, a bit older than me with short black hair and dark eyes. I instantly find him creepy. Train arrives and we enter. Now those trains have two levels with [stairs](https://upload.wikimedia.org/wikipedia/commons/thumb/3/3d/Metronom_2010-07_02_%28RaBoe%29.jpg/146px-Metronom_2010-07_02_%28RaBoe%29.
jpg) at each end of a wagon. I get a seat at the upper level next to the stairs while he proceeced to sit down in the inbetween of the stair area.
He stares at me the whole time, I try to pretend not to notice, but he's really creeping me out now.
I try to tell myself that it's nothing and the train is full so everyone tries to get a seat wherever there is a free one.
We arrive at Zoologischer Garten and I go down to the subway. There, creepy dude approaches me and asks me for the time. I pretend and act like I have never seen him before and tell him.
But I am afraid now and am thinking about going upstairs and finding police for help, but then the train arrives. I get into the first wagon and so does he.
Now I'm debating with myself if I need to go to a police station or if I try to lose him on my own.
I decide on trying to lose him on my own first, and if I can't shake him off, then I'll make him follow me to a police station.
We arrive at the next station and I and get out and move towards the end of the train, not looking back.
I hear the signal that the doors will shut now, I wait until they begin to shut and jump back onto the train. As the train begins to move I look out and see the guy on the platform. He's *pissed*.
Jumping up and down, kicking and punching the air. I'm instantly relieved, but my heart is pounding now, as my fear was right.
Now, had this guy played his cards right and not become cocky and approach me while at the subway station, I don't think I would have noticed him follwing me to my destination.
I regret now not going to the police afterwards, because this guy was not just thinking of robbing me and I'm sure he learned from his mistake. I could have at least identified him on a video. :/
Luckily, I have never seen him again and I continued to live in Potsdam for a couple of years before moving back to Berlin.
I also don't know if he just noticed me a the train station or if he already had followed me there.