What is the Appropriate Level of Irritation?

Look, it's a coffee shop and so people should be allowed to engage in conversation. Right? It's not like we're at a library. If I were in a restaurant with other people, I wouldn't necessarily hear other people's conversations because I would be involved in my own. But...I don't really want to listen to two people hold court on the state of education for children today.

Large woman with two colored hair, a black lace shirt, and a matching fat baby: "I definitely encourage you to um...think about how if a child's behavior is negative over and over, something is reinforcing that."
Thin man, black knit cap, blue camoflague pants, long shaggy goatee and moustache, blue bracelet like tattoo on his wrist, and small round glasses. HATE HIM: "I am really interested in the possibility of pursuing an educational resource for small kids." (Sips coffee).

That's not the best example of the dialogue, b/c I'm just typing what they're saying right now. I did hear her say, I don't believe there are bad children. I believe there are bad circumstances. Now she's giving an example of how she taught her son? daughter? Jessie to dress appropriately for the season instead of wearing his/her pajamas to school in the winter. Why does this kind of thing bother me so much? Well, for one thing, he just snapped his fingers to make a point.