Honestly I don't know why people wear headphones at all outside. I mean, I get we should all be able to hear our tunes or podcasts or whatever, but unawareness of your surroundings can change your life for the worse very quickly.
I seem to recall an ad for some product in the last couple years that still lets you hear what's around you with clarity while listening, though I can't seem to find it now.
The reviews are iffy on them though. idk, I just don't want noise cancellation until I'm someplace I'm going to be sitting in a long time that has sounds I don't want to hear.