The Holocaust was a major event (I guess I can't say worldwide--while WWII was somewhat worldwide, the Holocaust was mostly Europe) that involved many countries, and yet there are Holocaust deniers. Not just a couple, either. Whole countries/regions of the world teach it as a hoax! So there are apparently quite a few people who believe that millions of people can make something up and convince others with false evidence.
We could never keep people happy with the really popular (racy) orange fiction, either. People wanted it set aside on special shelves, which we tried to do. But that was really difficult because the books weren't marked in any way, so we'd pull out a selection of stuff, but people would get upset that not *all* of it was on the special shelves, or that it could be in two places. And the theft rates were incredible, something like 90% every few months. You really had to feel bad for the regular readers of such books, because they basically had to have a hold on a book when it was still on order if they wanted to get a chance to read it.
I remember some of the rather strange patrons we had, like this very nice, normal-looking mother and son who needed a search on various ghost/alien books that became stranger and stranger until it led to a search on how to make working tinfoil hats...
And there was this one very nice older woman who was constantly coming in with assignments from her church. She was very sweet and polite, but those searches that the pastor asked them to do for Bible study were crazy! She had this one assignment to look up information about Matthias, who was the apostle who replaced Judas. There seems to be less available on him than on just about any other apostle, but she needed an incredible amount of detail. If I remember correctly, there were two differing accounts of how he may have died, both by different methods and some difference in years, but she was so upset because she was sure she needed to know for *sure*. I really, really wished I knew what church (no idea how mainstream it was) she went to so I could call her pastor for her and talk to him about the level of research he was requiring.
Slightly off-topic, but our current library (I'm not working there, just using it as a patron) has a guy who has "Alpha-Omega" (the letters, but I don't know how to make them here) written or tattooed on his forehead, and his car is *covered* with signs and rantings. Papers in all the windows and on the sides of the car, and then some sort of giant mast attached to the back of his car and sticking up about 4 feet over the top of the car, with a sign attached to the top that also says something about Alpha-Omega. I remember assuming he was a patron until one of my kids said, "Mommy, there's that car! You know he works at the library?" And sure enough, I noticed him shelving books. Not sure if he's a volunteer or an employee.