Not observing normal manners
“Can I get a... ” is a completely legit way to order. “Please” is irrelevant, so long as it’s followed up with a “thanks, man.”
Avoiding eye contact/sometimes flat-out ignoring others
Whether it’s a homeless person, a clipboard person, or an old college roommate, there’s really just no time to stop and chat.
Bad umbrella etiquette
There’s no room for anyone on the sidewalk because everyone has a enormous and totally unnecessary umbrella -- plus, the ground is littered with the abandoned carcasses of thousands of other easily destructible Duane Reade umbrellas.
Taking loud cellphone conversations in inappropriate places
On the subway. At Starbucks. In an open-plan office. On the street outside someone’s bedroom window who is really just trying to get some sleep, OK?! Wherever we go, we make it clear to everyone within three miles what we think of that Tinder guy's penis size and the color and consistency of things no one wants to know about.