That’s something I was taught very early on by a driving instructor. The first time I drove on the freeway I instinctively slowed down to let a slower moving vehicle merge from an on-ramp. I was chewed out for that and told in no uncertain terms that when it comes to right of way principals, it’s often more dangerous to be courteous than it is to stick to the rules of the road. (That’s not saying you should be an asshole at all times, just that blind courtesy can be really dangerous to yourself and others.)
