My sister has probably saved my life a hundred times over the years. Just this past weekend, she convinced me of the following truths, which changed my course of action in several instances just enough to keep me out of prison or safe from blunt instruments:
1) It is a bad idea to tell the dimwitted elderly first-time Mom sitting in front of you on the Acela that her monstrous screaming child should be euthanized.
2) Pigeon shit is not a biological weapon. Even if it lands on your sleeve.
3) It’s OK to be irritated with humanity; not so OK to yell, “Fuck you, I was sitting there!” And then swat people with your laptop.
4) Long Island Iced Teas: A Drink For The Beginning of the Evening, Not The End.
Jennie Smash 
it is ok to say that to the mom, i am behind you 1000%!