Just like a birder obsessing over little brown birds, once you really start paying attention to butterflies you’ll happily ignore a showy Red Admiral to chase after something small and dark and nondescript.
(Although honestly, I think little brown skippers like this one are actually quite pretty when you see them up close.) I think this is a Dreamy Duskywing, Erynnis icelus. It has a very similar-looking cousin, the Sleepy Duskywing or Erynnis brizo, that can also be found around here, but since the Sleepy’s host plant is oaks (not terribly common around here) while Dreamy’s include willows and aspens (both very common around here), I’m going with the latter.
As with birds, you can learn to identify general groups of butterflies even if you don’t instantly recognize species. Duskywings are part of a family called the skippers, which are mostly quite small and share a distinct shape – stout bodies with relatively small wings, and a kink near the ends of their antennae. If you’re interested in getting to know butterflies I would highly recommend the book I use, the Kaufman Field Guide to Butterflies of North America.
Really, I just like the whimsical names. Dreamy Duskywing? I want to meet the entomologist who came up with that one and shake his hand.