Here's another reason why I don't like sitting by the window, if I had the choice to not. This morning, in a crowded train, I sat in the window seat. I noticed some gum wrappers on the floor, but no big deal, I sat down on the seat. Then, as I settled in, I noticed the sliver of space between the seat and window had a large medley of trash stuffed in there. I was grossed out, but for some reason, I felt the urge to look what people were stuffing in there. I saw individual-sized Doritos bag, straw wrapper, Saran wrap, portions of a mini-donuts plastic wrapper, and a Peet's napkin. Impressive amount of trash for a small space.
Of course it doesn't surprise me that there are inconsiderate passengers on BART. Personally, I don't EAT or DRINK on BART, since that's the rule anyways. But if you choose to sneak a few bites of breakfast or snack, please have the courtesy to pick up after yourself and not leave trash on the seats, or even STUPIDLY trying to hide the trash by stuffing it in between empty spaces.