Slow Clap
I was a lifeguard at a well-known chain of indoor waterpark hotels in the US, and a woman was letting her less-than-two-year-old daughter play in the shallow end all by herself while she sat in a chair and read a magazine. I walked up to her to let her know that it was not safe for a child that young to be by herself.
The mom started yelling at me, telling me that it was not my business how she parented and to leave her alone. At this point, everyone around her is staring. Then, as soon as she finishes her rant, her daughter loses her balance and falls face-first into the water, and is too young to know how to stand back up to get her face out of the water and breathe.
I run in, grab her daughter, and bring her back to her. Everyone around who was staring began to clap.
Story credit: Reddit / phoenix25