I have only given blood once, in highschool. After that I came up with excuse after excuse when Canadian blood services called me (I just got a piercing, I just had a tattoo done, I just got another piercing, etc.). I'm not sure why I kept putting it off. Fear mostly, I suppose. I don't like needles (I don't think anyone does) and I'm not a huge fan of large quantities of blood.
By some twist of fate I was given the day off of work and as I was walking back to my car I noticed the 'blood van' and I thought 'why not return the favour to the universe?' I am not normally superstitious but I do believe that if the universe gives you something you should give something back.
So take some time today to give back to the universe.