I have an appointment to donate again on the 13th.
Many years ago I worked in fast food and we had a regular group of customers that would come in every Wednesday (seniors day) twice a day, as we had a morning special and an afternoon one.
One day I had missed the morning to go donate, and was there for the afternoon. One of the elderly gents mentioned he'd missed me that morning, and asked about the bandage on my arm with polite concern. I told him I was just fine and that I hadn't gotten a blood test or anything, but that I'd donated. He nodded thoughtfully, then sat down to have his pie and coffee. I noticed he left much earlier than he normally would, as he came in regularly with his wife and another couple to socialise.
As it turned out, he hadn't left early at all, but had actually gone to a florist's up the street to buy me a VERY large and beautiful flower arrangement. He gave it to me and explained he had a medical condition that required him to have regular blood transfusions, and he wanted to give me something as thanks for donating.
I haven't worked at that job or seen that gentleman for many many years, but I think of him every time I donate.