I understand the reason that bicycle pedals are oppositely threaded on either side. What I don't understand is why it works because I'm missing something.
Take the right pedal for example. It's threads are right-handed, so it would be tightened by turning it clockwise (if the pedal were in between you and the bike). Now imagining this from the same perspective, a person pedaling makes the right pedal constantly turn counter-clockwise, relative to the crank. If there's any friction between the pedal and the bolt attaching it to the crank, I would imagine that it would create a force that would try to turn the bolt counter-clockwise along with the pedal.
This is the opposite of what happens, and I've seen the bolts unthread after pedaling backwards a lot myself. What am I missing?