Do stories need conflict?

In school we teach kids that good stories have conflict and have them fill out plot diagrams, analyzing the different parts relative to the conflict of the story.

Every time this comes up, I always wonder about its universality. As it's taught to kids, this is "how stories are" and conflict itself is considered essential to storytelling. The conventional wisdom goes that a story without conflict is "boring".

Is this the case, though? It's always felt to me like a very limited way of looking at stories -- fine for children but something that doesn't necessarily scale up past the early stages of literary analysis -- but I don't have anything to back that up. I don't have enough in my repertoire/expertise to really go beyond it, and I'm left with just a sort of empty suspicion that may or may not be justified.

• Is conflict essential to storytelling?
• Are there examples of good stories without conflict?
• Is teaching narrative in this way effective, or limiting?