Elm Idioms for Idio...Dummies

Important: I don't have a speaker chosen per se, so much as I'm willing to speak but would be happy to yield the floor, since I went last time. Even if you'd only like to discuss one example for five minutes, our door is open!

This time at Elm Portland, we'll be covering Elm idioms: how do you handle common use cases? Maybe defaulting? Task chaining? Where do you put your Message type relative to your effects, state, and update definitions? Bring questions! Bring excellent examples from around the web! Bring brain-bending conundrums!