Yup, I'm a "20 something" donation guy. I hate needles being stuck in me, but I just don't look.
Makes me feel good that I'm doing something completely for someone else and not myself.
As the needle is about to go in and that little bit a "sharpness" (which is over very quickly) is about to come, I just think "this is for you" (thinking of whoever will benefit from my blood), and that keeps me calm about things.
My thinking is that if I can put up with a 1/4 second of mild discomfort, then that can literally help save a life then I'm happy that I have the opportunity to do that.
I have worked a lot in operating theatres in the past, and can visualise exactly how vital it can be, which helps too.