Read, knitting/crochet, sleep, listen to music, play games (eg. emulator + pokemon games), study, read a newspaper, do crosswords, play chess online, watch a movie, listen to a podcast, learn a language, talk to other non-scrolling people, and yes, you can also stare outside, daydream or self-analyze, or even do nothing. Just a few decades ago we had a lot of dead times, it's not that crazy to pass an hour without having anything to do.

Reading and conversing with a stranger? Maybe not every time but at least once in a while?

I treasure my memories of being on subways and busses and getting lost in thought while staring out the windows, yeah. I mean, people have done this for basically all of human history (okay walking or something, not on a train, but, yeah). It's not a bad thing to have some time with just your senses existing in the world.

Thinking. Taking notes, ideally on a piece of paper. Relaxing. Talking to strangers. And yes, self-analysing. Staring in the window, maybe not so much.

its ok to just be bored. that was life in the 90s for me