Yesterday I got home very happy after a glorious session, in which I didn't climb anything hard in particular, but I had noticed great changes in my moving.
I was reflecting over this happiness later, and I understood why I was happy: because I dared to be happy.
I, sometimes, don't dare to be happy, for fear of failing. I choose the sureness of the "not being unhappy" rather than the chance of "being happy".
That's the same reason why sometimes I don't give myself 100% to a boulder problem: if I quit without having given my whole self to it, I can always think that I haven't done it just because I still could have given more. I can think "Oh, well, if I'd given everything I'd have climbed it". It's a bastard way of thinking, it steals my happiness.
So, I think I always have to give my entire self into the quest for happiness, for the most complete and full happiness, because, when I succeed in it, the reward goes beyond any imagination.