On a trail race or group ride I find if someone has a super bright light it can be a problem to those behind who don't. Shadows cast forward can be a real issue. On the road as a single bike in context of cars it is another story. When I had a 1 watt LED CatEye light people would High flash me either as a percieved favor or to identify the source. When I got my 10/20 watt Niterider it changed to cars turning down their highs from a distance. If they didn't I could click the high and they responded, just as in the car. Power used properly can enhance the experience.