That, and most people are SO easily influenced and lead astray ...
Remember those triangular UFOs that were all the rage a few years ago, from the early '80s thru' the early 2000s?
I created one of those triangles in a campground in the Sierra by stringing three little dim lights about 40 feet up, in an open space between some pine trees. Come later in the evening, we were all telling tall tales around the camp fire, as is typical in such situations. I told a story about my supposed encounter, on Priest's Grade/Coulterville Road (one of the many back doors into Yosemite), and at the opportune moment had my Wife turn on the lights and point up with a "Just like that one?".
The lights were just bright enough to fool the eye into thinking that there were no stars showing between them .... Presto, huge dark triangular shaped "craft" over our camp fire. When the wife shut them off after about 5 seconds, I yelled "Shit! Did you see how FAST that thing was?". One of the guys not in on the trick commented that it made it over the next ridge (about four miles away) in under a second. Strangely enough, almost everybody agreed with him. At this point, some people were claiming they thought it was redish. They got quite inventive about what they thought they had seen.
The oddest thing is that when I collected my wire and lights the next morning, several people asked what I was doing. I told them. They did not believe me! So I told everybody the truth about the hoax over breakfast. Most of them refused to listen, and today many of them still tell the story of the huge triangle craft hovering over our camp that disappeared like a bat out of hell when we all looked up at it.
I never messed with that kind of mass illusion again. Too much room for error.