It's not "the guy behind you" in most states I've driven in, it's literally half the people on the road. If you aren't driving the same speed as the people around you out of some misguided sense of self-righteousness you are actively impeding traffic.
I've literally been pulled over and told off (using much the same words I'm using now) for going too slowly on a freeway. I was religiously driving the speed limit and the rest of the traffic wanted to go faster. I corrected my behavior at that point and started going with the flow.
Doubt away, but I got a thorough telling off and started going 5-10 over like the rest of the freeway and haven't been pulled over since. Maybe your state is different?
No it's not. It's annoying, not hazardous.
> you're actively impeding traffic that wants to be going ~13mph faster than you are.
You DON'T break speed limits because the guy behind you wants to break speed limits. That's a terrible reason to break a speed limit.
And if you're the guy breaking speed limit and pressuring the drivers in front of you to do the same, you're actually the hazardous one.