We both like to climb. I am fortunate.
I guess the whole climbing (mostly descending) thing is why we got a tandem in the first place. My wife likes to climb, but her ideal ride on her own bike, would be to climb to the top and then get a ride back down. She just does not feel comfortable descending.
The strange thing is that we now do most of our riding (including lots of climbing as well) on the mtb tandem. The singletrack just makes it more interesting. If you think you get a lot of comments and looks on the road tandem, try offroad, people look at you like you are from another planet!