I have been donating blood since I was 18 years old. When I turned 37 years old, my father had cancer and needed a transfusion. At the time I had donated 4 weeks earlier and was not eligible to donate to him directly.
This experience was the first time it really hit home, on a personal level, regarding the need for and benefits of a blood donation.
When my father received the blood transfusion, it was like night and day. He was back with us for a while. To see the effect the transfusion had on him was almost like magic. My father eventually succumbed to cancer. However, this experience renewed my desire to donate as frequently as possible until I pass on or am no longer eligible.