Did anyone mention what I read here when I first started? "Smile on the hills". I have tried to do this and it helps- the explanation was that it helps you relax. Maybe it's a placebo effect, but I think it helps me.
As for being defeated by hills- I've really just had 3 or 4 that I couldn't finish by pedaling. One hill was ieast of Oakland California that on a ride with friends who live there. I made it slightly further the second time we rode it, but still just couldn't quite get to the top. Another time I got stopped was at Madera Canyon- riding on my touring bike with my panniers loaded up for a camping trip. I think it wasn't the grade but the fact that we didn't eat dinner and was bonking, but I walked for a while. (and it is steep- up to 10%). The other hill that really got me was in Ireland last summer. The directions mentioned "steep undulations" and suddenly, we descended into a little valley with a stream at the bottom. As we climbed out of the valley, I saw 15 or 16% on my Garmin and realized i was not going to be able to keep turning the pedals so I got off and walked to the top of the hill.
Kernowcyclist- 15-25% ??? For how long?
I can ride up hill for a long time (with rest stops) but I'm also super slow. I have gone up Mt. Lemmon twice already this year- climbing from 2500-8200 feet over 30 miles (with a flattish approach for 5 miles at the bottom, and some downhill near the top, but mostly climbing)... but it takes me about 5 hours. Only 1 1/2 hours coming down. So at 5-6% grades I go 5-7 mph. Slower when it gets steeper.