It would lead to becoming a healthier person.
You can... Chronic Kidney Diseases doesn't't mess heavily with overall blood composition, neither does spread between people or is dangerous to donate. There are several instances where one may not donate blood; blood transmitted disease like HIV or Syphilis, or a clotting factor deficiency, which is hemophilia, which while not exactly anything to worry about bloodwise, is much more dangerous to the person donating it, as without proper equipment or medication, a patient can bleed out.
The assumptions that certain races are lazy or dirty or uneducated makes employers reulcutant to hire them. Mostly same with women. Assumptions on strengh, willingness to work, and place in society makes employers biased and more likely to hire white men.
Smoke is very unhealthy for our body