Do not try to engage a mother with a crying, thrashing, kicking, screaming child. Don't say some pointless, mindless drivel such as "looks like someone's having a rough day!" Because you know what? She won't be able to hear you anyway, due to the aforementioned screaming child, but she'll probably still feel obligated to stop and say "What?" because you're still looking at her.
And it also doesn't help to say "Yeah, most little ones don't like (insert whatever activity it is that you're doing) very much..." and trail off with a look that makes me think you think I'm crazy for attempting said activity.
So here's what I wanted to say:
"Know what, dude?
You're here with two dogs.
I'm here with two kids.
Who do YOU think knows my kids better? You think it's you, with your two huge dogs and your permafrown? Or you think it's me, the one who stopped to talk with your unpleasant ass while I've got an obviously unhappy little one?
"Furthermore, my children do usually enjoy themselves here. Turns out, this one here (motions to Glamour) is flexing her two-year-old feelings. She doesn't show them often but when she does, they are FIERCE. That one (points to Glitz) is being surprisingly well behaved today, probably on account of the fact that her sister is being a hellacious monster and you're a potential tricky person with two huge scary dogs.
"Now can I continue on my way down the path here? I can see that my screaming child is annoying you, and I'm so very sorry that I stopped you and inconvenienced you with my stories about my kids.
Oh wait. That's right.
I DIDN'T. "
But since I really had no intention of actually stopping and making small talk, what I really said was:
"yeah, she always screams like this when I take her out of her cage."
The looks on their faces was priceless.