Well, it could be that all the empty rows are facing backwards, and your seatmate hates facing backwards on a train. I don’t mind it for short rides, but if I’m going on an extended Metro jaunt, I’ll share a front-facing seat rather than grab a backwards-facing seat I’d have to myself.
Perhaps there aren’t many empty seats, and your seat-mate thinks the ones available all look nasty - not uncommon on public transit.
Maybe your seat-mate saw someone else they thought would want/need the empty row (old woman, person with walker, very obese person, etc) and is trying to be polite.
Maybe they just didn’t notice the empty seat.
Or maybe there wasn’t an empty seat when they sat down next to you, and they don’t want to bother moving just because one suddenly opened up.
Look, I prefer grabbing a row to myself, all else being equal - but it often isn’t, and that just isn’t a big deal. shrugs
They want to tell you about the tracking chip the gang mob planted in their head, and the electronic stunning device the government is zapping them with in their sleep. That, or they want to know what kind of underwear you have on.
It only bothers me when it’s obviously a guy being weird, which has only happened a couple of times in years of riding the train every day.
I don’t know why they do it. The only times I have were when a seat was seriously disgusting, which has happened once or twice.
Maybe some of them are painfully shy and nursing a fervent hope that you will make start making conversation with them and (insert necessary storyboards, timeline and musical scores here) eventually live happily ever after?
Creatures of habit who like to sit in specific rows. People who aren’t paying attention. People who don’t like when someone scary, smelly, or otherwise objectionable eventually ends up sitting next to them, so they pick the most innocuous looking person on the train and sit beside them.
Damn it, this might be it. I look too innocuous. 80% of my train rides are to/from work, so I’m sitting in business casual, quietly reading a book. They probably spot me and think “She doesn’t look like trouble,” so these meek old ladies sit beside me hoping for a quiet, pleasant ride. Wrong move on my part. From now on I’m coming to work in my pajamas, unshowered, smelling like yesterday. We’ve got a gym downstairs; I’ll shower and dress there. I’m so doing this.*
Or maybe I’ll be the loud a-hole talking on a cell phone that nobody wants to be near, except who would I call that early in the mornig? Seriously, who are these people talking to at 7:30?
And they’re hoping that you’re not wearing ANY undies.
Usually, the people who sit next to me on public transportation are harmless enough, except that they want to talk. And talk. And talk. And they won’t take a hint that I’d rather think about things quietly, or read my book. They assume that everyone else is as eager to talk as they are.
Sometimes I feel weird moving, like will it offend them? (Not necessarily in a totally empty train situation, just a situation where there’s an empty seat I’d prefer to sit in because there’s more room.)
Spread out. If there’s even the slightest hint of a confrontation, those who are looking for the safe seat will never choose to sit beside you.
The GO Bus I take usually has enough seats that each rider can have two. For some reason people would always sit beside me even when there were many sets of two still available. I now (on the day I still go into the office) put my laptop beside me. On the rare occasion that the bus starts to fill up I immediately move it.
These are the first people I choose to sit next to, purely out of spite. Not if there are empty seats, of course (and you mentioned that you move your stuff if it gets crowded, so this doesn’t apply to you anyway), but if the train is getting full and someone’s got their shit spread out all over, I make a beeline for that seat. I refuse to allow them to have a seat to themselves on a crowded train just because they’re obnoxious.