(Here is another Public Service Announcement on this topic, seems it fits so well with Jcliff's success story.)
After you have donated blood for a while, the blood bank starts giving you T-shirts commemorating the total number of gallons you have given. So whenever I feel the World is ignoring me and I don't feel like blowing up a building for attention that day, I put on a blood bank T-shirt and go to the grocery store. For every $30,- worth of groceries I put in the basket, one person breaks into a smile, reads off the number of gallons posted on the shirt and generally chats me up in a cheerful style.
