Commuting via public transportation can be a wonderful thing; you don't have to drive, it's good for the environment, it **usually** carries on despite in-climate weather, and so on. That said, it can also be completely awful. The buses in Boston get crowded sometimes and the trains even worse. For the most part, my fellow commuters are well versed in public trans etiquette and despite being nose to nose with them at times, are acceptable traveling companions. However, on occasion there is that outlier, who's bad day, addiction and/or mental illness ruins it for everyone. Not to mention the smells (namely urine with the occasional errant bus-fart) and sounds that one is assaulted with 5 days out of the week (the squeaking brakes between Harvard and Central are ear splitting).
Most people deal with the conditions (and don't forget boredom) by distraction, namely via the smartphone. In addition, music is a popular distraction (for the most part using earbuds/headphones - don't get me started on the assholes who opt for their phone's speakers...). This is what I for the most part did, in the beginning of my public trans days. Staring at Facebook while listening to music on my over-the-ear Bluetooth headphones (to hell with wires).
But one can only refresh FB so many times before your brain starts to go to shit. So one day, I started sketching on my phone, using SketchBook Pro , with a recently acquired Wacom Gen. 3 Bamboo Stylus .