So! Inspired by all the positive thoughts in this thread, when I saw the Red Cross Bus parked outside my office building on Tuesday, I decided to donate blood.
I now have an 11 inch by 8 inch by 8 inch bruise in delightful shades of black, purple, yellow, red, and green.

About 90% of the way thru my blood stopped flowing and so I was prodded, poked, massaged and manhandled for the next 3-4 oz. Have to wear long sleeves or endure squeals of disgust and "Have you seen a doctor". I did call my doctor. Her assistant said "Ice packs".

This happened the last time I tried to donate in 1971. Never again...except maybe for Kendall.