As long as you've got a good level of cycling/cardio fitness it's 90% in your head. I can only speak from my own perspective as a fellow hater of hills when I started out... in the first couple of months of "serious" riding I'd have to stop part way on any climb over 10 minutes long with my heart rate at 170+, but once I'd built up some fitness & stamina by putting in the hard miles, I was away.
It could be just your mindset that isn't right - it takes a special kind of masochism to really enjoy the physical effort of riding up a 10% gradient for 20 minutes, all the pleasure is in the satisfaction of making it to the top (personally speaking). Even better if you did it quicker than the last time you did it... but don't expect it not to hurt, ever, it always hurts if you're putting in the effort!
So, as stated many times already in the thread, get in the right gear for the hill you're facing. If it's a short steep effort that you can tackle in under a minute, carry as much speed in as you can safely & try to power up it as far as you can out of the saddle. If you have to sit down & spin the pedals for the last 100 yards so be it, you'll improve the more you do it. Have a rest at the top & get your breath back, carry on satisfied that you made it.
If it's a longer effort, get in the correct (low) gear and spin up. Start off in the absolute lowest gear if you must, if it's too easy flick up a gear or two. I distract myself by checking my heart rate as I go; if it's around 155 I know I can carry on at the pace I'm travelling at for a while, even if my legs are complaining... and that's where the mental side really comes in - ignore the pain, once you've proven to yourself you can do it it's all about fitness & stamina. Concentrate on breathing properly, don't strangle the handlebars, keep a nice, steady, even rhythm on the pedals. Stop at the top and have a drink, you've set a benchmark to aim at next time you do it.
And lastly don't fret about weight loss, if you're born to be a mountain goat you'll lose weight by climbing more hills...