This afternoon, I went to a church hall, lay down for 20 minutes, had a cup of tea and a chocolate biscuit, and went home.
Someone very close to me has to be given three bags of blood, every three weeks for the rest of her life. Any donor can only give three times a year, so it takes eighteen people donating blood, never missing a session, to keep that one person alive for a year.
Someone badly injured in a car crash, or with a critical internal bleed, might need 20-30 units of blood. That's ten people's donations for a year, gone in a weekend.
It really isn't a big deal. It's a little needle. It's very quick. You get free biscuits. Free. Biscuits.
If you've ever thought oh, I should give blood one day, please make that one day an actual day. If you are in the UK, check out the NHS blood donation page. If you are in the US, check here.