Ugh, this happens when I ride with my dad. I'm faster than him going up the hills. I only ride with him occasionaly, but when we do, I always ride with him going up the hills or if I get ahead, I slow down for him to catch up. As I see it, we're out for a ride together. I know I could charge up the hill and leave him in the dust, but it's not a race and we're out riding to enjoy each others company. But the second we get to the top of the hill, he takes off leaving me in the dust. It drives me crazy!
The way he sees it is that he's getting old and doesn't want to 1. show is age and 2. be beaten by his daughter. He feels he has to prove to himself that he's still strong and says stuff like "You can't keep up with me on the downhills." And "What's taking you so long?" And I have to hold back so hard from saying anything because he's VERY sensitive and defensive about it all.
It's only worth it if you're having fun