I was never the biggest fan of needles, but two of my friends were going to give blood and I was roped into going along as well.
When we got there, one friend had too much alcohol in his system and as such couldn't donate. With the other friend, the nurses couldn't find a vein!! So despite my protests over not wanting to go, out of the 3 of us, I was the only one to actually donate on the day.
I believe everybody capable should donate, although I believe they should donate because they 'want' to as opposed, to it becoming compulsory