Q. At the park, I saw a mom scream at her teary toddler for dropping her cup in the sand. I suddenly felt protective of the kid and wanted to tell the mom to lay off, but didn't know if it was appropriate. When can I speak up, and when should I mind my own business?
A. Is it hot in here? Or is it just uncomfortable for me and millions of other moms living in glass houses?
Yes, that's my ham-handed way of saying that I too have lost my patience with my kids for acting like children. It's also my way of saying that the particular scenario you describe doesn't require you to throw stones.
But you can tap on the window to get her attention.
Since there was no way to assess what was really going on from the scene you observed -- maybe that was the hundredth time her kid dropped the cup in the sand on purpose -- try and discover the back story by bringing up your own experiences. In other words, rather than reprimanding this mom, which would only stoke her anger, try using your voice to diffuse it.
You might say, "My son always does that when he's overtired. Is your guy ready for a nap, too?" or "When my kid does something annoying like that, I have a tough time remembering that he's a toddler and that's his job." Or even "I heard a little bit of sand in your diet keeps you regular." Whatever script you use, it's a good idea to add "It's frustrating, isn't it?" This offers her a dignified way out of her public anger.
She may appreciate your concern or she may not. She may start explaining why she overreacted or she may not. But one thing is certain: You'll not only distract her attention from her child, you'll give her a moment to consider her own reflection.