No, but it's fascinating to see people use confirmation bias with it.
(Success) vs (Failure)
"My prayers were answered!" vs "God works in mysteries ways."
"Karmic retribution!" vs "Maybe not today, but Karma will strike another day."
"My spell worked and he did end up hurt that day!" vs "Obviously my magical [insert whatever] was weak that day."
People who believe in some form of magic will generally put themselves in the position where failure can be explained away as anything other than proof that the magic in question isn't real.
As for the good ole' "sincerity of belief" argument, there were hundreds of people who felt pretty sincere about it when they chugged purple koolaid. Plenty of folks who thought the world was going to end in the 80's, the 90's, y2K, 2012, et cetera. Loads of people sincerely believed in Ra, and Thor, and Zeus, and did all sorts of magical rituals to worship and appease them. Emotional sincerity only shows how invested someone is in something, it is not an indicator of truthfulness or falsehood.
Then, others claim "why would a person lie?" I dunno, ask a televangelist how his income is doing. The charlatan will probably lie to you about that too. Aside from monetary incentive, someone could sincerely believe to have witnessed something paranormal that is easily explainable through other, more ordinary means. The door slamming by itself could just be the breeze or air you disturbed when you ran past it. That dream you had about your favourite sports team winning could just as easily be explained as statistical coincidence, seeing as how said team is likely only facing off against one other team, one of them has to win anyway.
Usually it then falls to "do you have a better answer?" Yes, I do. I don't know. That's the answer. If you encounter something and you don't understand why or how it works, that does not make it magic, nor does it make it the work of a god, nor does it make it a moment of karmic reward/punishment. UFO's aren't alien aircraft or top secret government spy planes, they're unidentified flying objects. It should just as easily be an aircraft you simply didn't recognize, or something else you didn't even know was real. The guy you hate getting hurt the next day doesn't mean you have a special power with Jesus or Buddha to enact your revenge, it just means he was hurt that day completely separate from you.
If there's one thing I've noticed about this paranormal, supernatural stuff, it's that it's always an egocentric relationship with it. People just happen to "know" that God was responsible for something in their lives whether good or bad. Same goes with karma, or any other form of magic. God looks, sounds, and acts astonishingly like whomever is speaking on his behalf or interpreting his actions. Magic seems to work to whatever set of rules seem most convenient for the person using it, almost as if it was tailored to their wants and needs. Hmm.
I have things in my life and in my past I cannot explain, but I don't need to try and explain them with a supernatural force that only opens more questions rather than giving me answers. Besides, life is better with mysteries and the unknown. Best leave it that way.
