I was at the gym yesterday, in the zone on the elliptical with my favorite book, when two teenage girls hopped onto the machines next to me. Their giggly girly energy, coupled with the music one of them was playing on a phone, irritated the crap out of me. Then I realized that, being teenagers, they'd likely move on to something else within 45 seconds. I was right. I congratulated myself on sticking to one thing.
For whatever reason, it reminded me that I used to do a lot of things all the time. Now I do just a few things the best I can, and ignore the rest. Call it selective multitasking.