I was at my apartment's gym and this bro kept dropping his weights from about 2–3 feet above the ground and after the fourth loud bang I kind of lost it and went over to him and said:
"If you're not capable of lifting that weight without dropping it, then you're not capable of lifting that weight."
So I guess I’m never leaving my apartment ever again.
@Alice Heh. I was at a concert that I'd been looking forward to for 6+ weeks -- I struggled to get tickets, but eventually snagged a spot in the 10th row. During a really quiet and low sax solo, two girls standing behind me were chatting loudly.
I turned around and said "LISTEN NOW... TALK LATER." And they were immediately silent.
I felt bad about having to call them out, but after the song was over I turned around to thank them for being quiet for the rest of the song... but they were gone. I didn't see them for the rest of the night, so either they weren't into it and left, or I shamed them into going elsewhere for the rest of the show.
Either way, I enjoyed the rest of the concert.
@JustinDerrick I did something similar at a movie theater when the guy in the row in front of me kept pulling out his phone to swipe on tinder (at full brightness, of course).
Like bro, I paid to watch a movie, not your sad dating desperation.
Alice McFlurry 
Justin Derrick