People encroaching on your space. Man spreading, bag spreading, coat spreading, spreading waist, whatever. Not my problem, if you don't fit in your seat you can hang off the far side, you aren't entitled to share mine. Fuck off.
Phones on speaker/ face time. No Caitlin, nobody but you cares about the saga of your friends love life, put the phone to your ear, not your chin, or put it the fuck away.
Shit parenting. I won't judge you for what your kids do because I don't know the full circumstances. But if your dc are being annoying and you sit there with a proud indulgent smile, or worse look around smugly under the illusion we're all impressed by your little cherub, then you can fuck off.
People sitting in your reserved seats and instead of moving, attempting to guilt trip you into giving them up. Fuck off and ask someone in unreserved seating to stand.
People, mainly older or pregnant addressing an individual, in a priority seat under the assumption they are being lazy and can't possibly need it. If you need a seat, address everyone, don't direct your comments towards whichever person you have decided on appearance alone is less deserving. And if you do, don't be surprised or offended when you are left looking a fool.