Ear buds. I don’t understand why cyclists use them. I can understand them in the gym. Maybe. But on a bike?
For one thing, they are dangerous. You need to hear the traffic around you. Vehicles approaching from behind, cars pulling out of driveways, and children playing by the roadside. But more importantly, they take you out of the moment. You want to be in the moment, fully aware of your surroundings. Not only the sounds, but the smells, wind, warmth, and views. If you are listening to music while riding, you diminish the experience. You need to hear, and feel, your breathing. You need to feel the burn in your legs. You need to feel the wind in your face, and the warmth on your back. You need to smell the sweet corn fields as you pass.
You need to stay in the moment not only to stay safe, but to fully experience and enjoy the ride.
PedalWORKS 
Can’t agree more on this. I see a lot of people on the road running or riding with hig headsets / earphones over their ears. Earplugs, earbuds, earphones and practically anything that pretends to mask your real-world feeling on the road is a dangerous distraction. For a cyclist this is added danger to an already exposed road, especially if there are no dedicated cycling lanes.
I used to but no more. Unless there is a very important cricket match on from Down Under on my way to work. And then it’s only one in the ear closest to the gutter (so I can listen out for the shiny metal boxes passing on my right…). Otherwise, I agree-let your senses be free to soak it all in!