I'd argue in my case I should in fact be driving 80 mph a lot of the time, because everyone else is, and it is safer to go with the flow of traffic than it is to follow the letter of the law. As I'm sure you're aware, non-head-on collisions become more dangerous when the delta between speeds of the colliding objects are divergent more so than they are impacted by absolute ground speed of the colliding objects. In fact, even the DMV tells you to disregard the speed limit if it is at odds with the natural flow of traffic speed.

FWIW, I only ever drive 80 mph in 65 mph zones on large 5+-ish lane freeways. On non-freeway roads, I don't speed.