Welcome to a special summer-school edition of my favorite course, “Public Transportation Etiquette.” This is an AP-level class that will assume you’ve already mastered the material covered in the prerequisite (no seat hogging, escalefting, door blocking, Metro munching and/or headphone blasting). In lieu of a textbook, we’ll be going over a few recent scenarios I had to sit through. And now you have to sit through them, too.

Chapter 1
On the 32 bus as it was cutting across the National Mall, I caught a whiff of a strange scent. I popped my head up from my paper to see where it was coming from, and that’s when I spotted a woman a few rows ahead of me painting her fingernails. A handful of personal grooming tasks are acceptable on public transportation — applying lip balm, for instance, is fine. There’s nothing acceptable, however, about opening up a stinky bottle of chemicals that could easily spill. Metrobuses are in need of a makeover, but not a messy pedicure. (Which is why you also should always leave your nail clippers at home.)

Chapter 2
You know what they say about the family that sits together? It doesn’t get on Vicky’s nerves. When a nearly empty Red Line train pulled up recently, I was eager to savor a few minutes of silence after a long day at work. I never got that because a mom and dad decided to sit at one end of the car while their teenage daughters positioned themselves clear on the other side, and they all proceeded to have a conversation. If there’s extra room and people want to sit on opposite sides of the aisle to have a chat, that’s not a problem. But this family’s yelling about which stop to get off at when they could easily have used their inside voices? Not cool, and not setting a good example for the next generation.

Chapter 3
People sleep all the time on the MARC Train. So when I sat across from a guy slumped to his side on an afternoon trip back from Baltimore, I didn’t think anything of it. Then we jolted out of the station, his eyes fluttered open, and he slurred, “Where are we?” I realized he wasn’t just tired. I’m pretty sure he was trashed. After he fell onto the floor multiple times, I excused myself and watched from afar as the conductors tried to figure out what to do with him. They managed to send him off at his stop, but that’s really not part of their job description. Drunken riding is always (always, always) better than drunken driving, but next time, buddy, don’t board until you’re capable of staying in a seat.