Because, you see, I now have an excuse not to have some strange person stab me with a needle. You see, I am a victim of Vaccinophobia, the fear of vaccinations and needles............
LADY WHO WANTS TO STAB ME WITH A NEEDLE: It won't hurt!!! just stop running away!!!
ME: YEs, it will hurt!!!!!! horribly!!!! i have vaccinophobia, stay away from me!!!!
LADY WHO WANTS TO STAB ME WITH A NEEDLE: oh, well in that case i'll go away and you can die from smallpox or something.
ME: but i won't have been stabbed. AHA!
apart from the fact i will now get really diseased.