I use mirrors in car, and on motorcycle often. Couldn't drive without them. On the bicycle: I took my mirror OFF. Why? Because it scared me. Cars drive as if they're going to hit me, then swerve in the last couple of meters. Normal driving habits in my city. Bicycle is too slow to do anything at that speed difference. Not enough time to even get off the road in time. So all mirror did was make me scared, uncomfortable. Not sure if I explained it right.