This a list of things many NT people do that are almost certain to make people on the spectrum hate them.
1 - Tell them "you don't look/sound/act autistic".
2 - Mention that you heard the latest mass murderer had Asperger's.
3 - Tell them "I heard Hitler was autistic, too."
4 - If the autistic person is non-verbal, talk as if they can't understand what you're saying and like they're not even in the room.
5 - Use " autism", "lack of", and "empathy" all in the same sentence.
6 - Wear ribbons or keep decorations shaped like a puzzle piece or a puzzle pattern or a blue lightbulb.
8 - Make lots of noise when eating, walking or moving around.
9 - Always sit or stand as closely to them as possible.
10 - Tell them to stop stimming, even if they are not causing any harm doing so.
12 - Tell them to make eye contact.
13 - Tell them to smile. Even NTs hate being told to smile when they absolutely do not want to.
14 - Two words: Autism Speaks!
15 - Have everything lit up in blue during April.
16 - Use "autistic" as another word for "stupid" or the "R" word.
17 - If they are visiting, have your TV or stereo on as loud as possible. If they ask you to please turn it off, react as if they asked you to give them one of your kidneys.
18 - Assume that anyone who acts rude, nasty, or gross must be autistic.
19 - Make fun of their special interests but talk endlessly about your own "normal" interests and expect them to listen just as much as they would like you to listen to theirs.
20 - Firmly believe that autism is a horrible national health crisis caused by vaccinations and that everyone should just stop getting shots, and stand by your belief even when the death toll from diseases that were once nearly non-existent start to rise. Also be sure to include fundamentalist religion and pseudoscience in your protests against vaccinations.
21 - Act as if only male children are autistic and that they somehow disappear from the face of the earth the second they turn 20.
22 - Believe with all your heart that people use autism as an excuse to be intentionally rude when most autistic people are not intentionally rude, often worry about when or where they will make the next big social faux pas, and are very embarrassed and will usually apologize when they do.
23 - Tell them "Oh I know someone named so-and-so and he/she has autism too. Do you know him/her?" because people on the spectrum *must* know someone else just because they are also on the spectrum. This is the equivalent of assuming someone of a different race, sexual orientation or disability must know all other people with the same similarity.
24 - Suggest (more like shove down their throat) they try all kinds of snake oil remedies that "cure" autism. Make sure these "cures" are as creepy and disgusting as possible and ignore the horror stories of people who tried them on their autistic children, and the kid got badly hurt or died.
25 - Tell them autism is made up and doesn't exist.