It's rather disconcerting coming home later in the evening on the train by yourself. First, there are fewer people around you (unless after a sporting event lets out). Although this sounds good initially, that old adage about safety in numbers rings true. Getting off the train in a moving carpet of people is quite different then getting off all by yourself on a dark platform with only the sound of your own shoes following you. Second, when you live a little outside the city, the windows on the train are darkened which adds to the spooky factor. Third, the trains take longer so you're standing on the lonely platforms longer. And fourth, the walk home in the dark by yourself is great on the nerves.
I used to love to be out by myself in the dark, when I was much younger, when I thought I was invincible. But life and circumstances can take something pleasurable and twist the shadows and sounds around you into your fears. That's another reason I don't understand why so many people have headphones in all the time. They can't possibly hear that rustle just behind them, that person rushing just outside their periphery. My mother used to say, "I know those shoes are pretty, but can you run in them." It's a comforting mantra in the dark.