Nearly all of my sexual fantasies are about giving pleasure. I imagine I'm feeling pain or nothing for the sake of pleasing a demanding but appreciative partner. He or she comes a million times, loudly and enthusiastically; if I come at all it's forced on me and it's painful. I imagine having things done to my pussy and ass that make them tighter and more pleasing but at the expense of making the sex horribly painful to me. (Meanwhile, of course, I'm giving myself entirely self-centered, not at all painful stimulation, but I don't really think about that.)
In my actual real-world sex life, it's not really like that. I enjoy giving, but I give and get in roughly equal amounts, and I like the getting too. The only caveat is that I can't stand to accept pleasure selfishly. I always want to know that my partner is hard and horny when he's licking or fingering me--not to flatter myself but just to be reassured that I'm not imposing.
Some of this is personal to me; I have an assload of sexual insecurity that's relieved when I feel I'm being generous in bed. (Actually, come to think of it, that thought isn't so personal as I know a lot of other people feel the same way. Including most of my partners, which has led to a lot of frustratingly circular "I want to do what you want!" negotiations.)
But it's not just insecurity. The other reason is that I can have an orgasm on my own. What I can't do on my own is watch a man have an orgasm from skin-on-skin distance, feeling his muscles contract, hearing the sounds he makes, watching his eyes or his face or his cock as he completely loses himself in the pleasure I'm giving him. That, not orgasms or penetration, is an experience I can't get anywhere else.
And it's goddamn beautiful.