as a microbiologist the thing that realy REALY shits me is the anti-vaccination movement. i can not think of a single group of people doing more to drag humanity back into the dark ages. i just want to cry every time i hear of someone dying of whooping cough or diptheria because they thought the vaccine would give them autism. that claim alone drives me nuts. it was in 1 paper, which has been retracted cause of shit science, 9 of the 11 authors have distanced themselves from the conclusions of the paper, and the lead author, and the papers only defender has now lost his medical licence, there is no way that can be more disproved, but no its all "I wont protect my child, and by proxy the community from this easaly preventable disease because it will give my child down syndrome. i know this cause a woman who could tell you what a fucking T-cell is said so" sigh, so much lost hope for humanity.
otherwise, as said above, arguments agaist evolution, "you cant prove evolution" I can think of at least 3 simple experiments to prove evolution happening in a clear and disticnt fashon, but even if i showed them, they would sill argue against it.