One thing I miss about public transit is being able to catch up on reading (whether academic or for pleasure) while someone else handles the wheel. I took the bus and trolley for about two years while going to community college, and I really enjoyed reading while the streets and trees and people flitted past the window.
Text itself, because of its nature as a code, lends a form of privacy to the reader. Unlike most images, a person has to decode and translate text in their heads in order to understand it. After many years of reading (or many hours of Hooked-On-Phonics), we've learned to do this fast in our dominant languages. Text, in its pure physical form, manifests as black marks across the page.
This is how I hid my naughty, inappropriate, and embarrassingly awful literary adventures from my mother for so many years--under the pretense of academic reading. Rip off the steamy, six-abbed cover of a Harlequin novel and you have an appropriate "literature" book... Anyway, I digress.
At first glance, a fellow passenger wouldn't really know whether I'm reading some high-brow classics, obscure hipster literature, or weird kinky stuff, unless the cover is extremely recognizable. And even this can be prevented by using an ereader.
Unless, of course, while I'm reading and having a great time, their rapidly-decoding eyes happen to land quickly on the words moan, caress, and thrust. Especially thrust.
To that poor passenger on the MTS back in 2011, I am sorry for what your eyeballs had to go through.
Someone I knew would take off the dust jackets of his books to read on the bus for privacy reasons. He said that with the huge tome, people just assumed he was reading the Bible and left him alone. I like seeing other passengers with books, and I was quite guilty myself of trying to catch a glimpse of the cover to see if they were reading something I recognize.
Nowadays, I drive to work, so I don't get the chance to read during transit. I tend to zone off when hearing audio books, even while on Zombies, Run! missions. But if you read on the bus, trolley, or train, kudos and happy reading to you.