Hills are enough of a challenge, I don't need to make it "worse". If I do come across a slower person, then I will keep my regular pace, only going faster if the space is narrow and I don't want to stick out into traffic but then slow down to regular pace. If he/she doesn't like me passing and want to race, then, IT'S ON BUDDY!!!, just kidding, I'll just let them have at it without me.