I will share one experience where I would have been killed if I was listening to earphones on my bike. I was with 2 other cyclists and we were crossing a busy 4-lane hiway with a center turn lane. The other 2 were stopped out in the center turn lane and I was just crossing the two lanes to get to the center. I looked to my right and there was one car stopped in the turn lane to my right and I didn't see (or hear) any other cars coming from the right so I was about to continue across the remaining 2 lanes. Then I heard one of the other cyclists say "car". There was a car coming but I couldn't see it because the car in the turn lane blocked my view. If I hadn't heard him say "car" I would have ridden out right in front of that (hidden) car which was travelling fast enough to kill me. When he said "car" it was loud enough to hear but he didn't shout it. If I had music playing and didn't hear him I wouldn't be here posting this now. Besides learning that being able to hear as clearly as possible is a good thing, I also learned that you do not cross a road unless you can see there are no cars coming - if your view is blocked you have to assume there is a speeding car behind whatever is blocking your view.