Originally Posted by
acidfast7
I ride in constant traffic. Either passing or getting passed constantly. A mirror would simply be a distraction but maybe you're conditions are different.
If I have parked cars on both sides of the street and two way traffic in addition, I don't have anytime for a rearward mirror.
That is the situation where they're most useful.
You know *exactly* where cars are, where the gaps are so you can set up better transitions, who's setting up to pass and turn in front of you (goodbye hooks), who's about to mess with you for sport, who doesn't see you at all, and who has stuff sticking out the sides (trailers, construction stuff, etc) and isn't thinking about that when considering their width, and who's giving you extra space so you can fit somewhere you need to be.
Ignore all that stuff, and you're relying on luck for your safety.