What if i want to listen to music on only 1 earphone for some reason? Like talking to someone while listening to music, or to listen to what's going around while driving?

I don't take the bus, I drive a car, and I'm not dumb enough to listen to music while walking around town. But listening to music while working out, then having a call come in, and have the music turn on by itself after the person hangs up, is great.

You might enjoy listening to a phone conversation with both earphones, but your fellow bus passengers are sick to death of you shouting into your phone.
Oh, and mind that reversing truck over there.

Sony Ericsson already has a great set of earphones, the HPM-70. You answer a call by pressing a button on the clip-on mic, and end it the same way. And listening to a phone conversation with 2 earphones is actually enjoyable.

Schrödinger's headphones?