Let’s bar all sex jokes and obvious stuff regarding health.
I had a thread a while back called “Things you didn’t think would get popular.” This is pretty much the same thing, only it’s about random, trivial stuff in your life you didn’t care about at first, but use a lot now. Again, the scale is wide. Maybe you originally didn’t care that a DVD had commentaries, but now it’s one of the primary reasons you’d buy a DVD.
-My MP3 player has an alarm clock on it. A few years ago, that didn’t matter at all. Now I use it every day to offset my awful sleep patterns and get to school/wherever on time.
-Podcasts. I never cared about them until I realized they’re easy listening for when I’m doing stuff around the house. Now I have a bunch of them I haven’t listened to yet.
-Smart Playlists. I didn’t care about them in Winamp (my primary music manager) until around a year ago, and now their automatic sorting has enabled me to download and burn through tons more music than I used to.