I'm not going to donate blood
Why don't you want to donate?
Because I think that the blood bank only needs the blood of people under 25.
Donating blood is an important act of altruism as it can save the life of many people in need. If you are in good health, you should consider donating blood so that people who need a blood transfusion will be able to get one when they are injured and in the hospital.
I just want to play WoW and be a troll, not being at the hospital.
While it's your choice to donate or not, it would still be a great idea to try it out! Maybe you'd have a great time there, or feel great that you are helping others out. The ones in need would thank you very much for saving their lives.