I’m lucky enough that the company I work for gives its employees one day of leave every year as a “good deed day”, which you can use to do a variety of things, including give blood - which is exactly what I did today. To be perfectly candid, 90% of the reason I donated 470ml of red goo is because I thought it was a good way to get a day off work, as the whole thing takes less than an hour. Plus it’s an excuse to eat a tonne of sugar for a day.
Fortunately I’m not too squeamish and don’t mind needles too much, and the whole process went pretty smoothly, I didn’t feel any different before, during or after. It was slightly disconcerting to see a bag filled with my own blood just sat there on the table next to me, but other than that everything else was perfectly pleasant. I even got snacks and a sticker out of it - overall a very worthwhile experience, given I get to feel good about myself and get a day off work.