I enjoy a gentle climb with plenty of switchbacks. Like, ideally rail trail gradient. You can zone out, have a chat, enjoy the sights and sounds. I can also agree with the last guy that sometimes even a road climb can be fun.
Hard technical climbing though, is a much more strained relationship, I go from enjoying the work, to indifference, to raging hate and frustration, and back again. I ride flat pedals as well, so if I don't get it smooth and perfectly timed, there's no power upstroke to save it. Hard climbing with flat pedals is especially masochistic. Steep fire trails I tend to walk, it's just as fast and less tiring.
On the weekend I got to the top of a climb somewhere in Garigal Gorillas territory and had a mini anger dance at the top. It was just pedal strike, walk, find a spot to remount, spin out (geez sometimes it was like trying to pedal through a ball pit) walk, pedal strike, walk....etc etc.