For me, it’s the fact that (to take a concrete example) you’re equally likely to win a lottery by playing 1-2-3-4-5-6 as you are playing 2-12-15-19-33-35.
I know they’re equally likely, but I would never play the former in an actual lottery? Why? Because it FEELS less likely (which, of course, tells you just how likely it is to win the lottery with ANY set of numbers, but that’s beside the point here).
You got any mental hang-ups like that?
I use the 1-2-3-4-5-6 thing every time I’m tempted to waste money on a ticket.
The old favourite Monty Hall. I understand it, but it’s not something that I can just subconsciously accept - I have to apply mental effort every time I think about it.
Similarly, that wind-powered vehicle that goes faster than the air blowing past it.
That solid matter is mostly empty space.
I don’t like tempting bad luck, though of course it’s bullshit. I have little bad-luck tics like knocking on wood and not saying something will come out well before it does.
I understand that of course it’s all superstition but I just can’t shake it.
The uncertainty principle in quantum mechanics.
The concept that human civilization is 6000 years old, making it a tiny millionth of a fraction of the age of life on earth (3.8 billion years) and the universe (14 billion years). Technological civilization only started 300 years ago. I can’t imagine life any other way though. Richard Dawkins once said that if biological life were the length of a human arm (3.8 billion years) the entire history of human civilization would be the skin cells on the end of your fingertips that you can scrape off with a nail file.
You probably know this but using 1-2-3-4-5-6 is a very bad idea because other people do it to. The only thing you can do to improve your odds in a lottery is to minimise the chance you have picked numbers other people will also pick because it dilutes the winnings. Any recognisable pattern that other people might pick is a bad idea.
Atheism. It makes perfect logical sense to me and it matches my observations about the world to a tee.
But I’ll admit even I have moments where I wonder what’ll happen if I end up being wrong about that.
Adding to the probability one, I still feel like if I flip 5 heads in a row, the next flip has just gotta be tails. I know the coin has no memory of its flips and there’s no reason for it to prefer one or the other on any given flip, but it’s a hard feeling to shake.
Skyscrapers. Specifically, that those gigantic 30-story steel towers were actually built by people.
I know it’s true. I’ve watched it happen. I’ve driven past construction sites on my way to work, day after day, watching the whole process, step by step.
But… I look up at a finished skyscraper, and my mind refuses to accept it. People could not have built this; it’s too big. It simply could not possibly have happened that way. My gut rejects what my mind knows full well to be true.
(So…I listen to my head, and buy my gut a cheeseburger now and then.)
Driving in a car is statistically more dangerous than flying in an airplane. I know that’s true. But still; driving is ON THE GROUND. If you crash, you’re already ON THE GROUND. If your airplane crashes, you will also wind up on the ground, but only after falling through several thousand feet of sky first. Just seems wrong that planes are safer overall. (I understand why they are; it just feels wrong.)
I periodically return to the conviction that identity is an illusion. But of course I’m thinking to have such a conviction, so how can that be? I haven’t sorted it out, so both sides of the equation can appear false yet obvious.
Radio. What the fuck, seriously radio. See also wireless anything!
Funny you should mention that. Two weeks ago I bought a computer generated lottery ticket. The numbers were 20, 21, 22, 23, 24 and 33. I showed it to my wife and we both laughed. She said - well, it’s got as good a chance of winning as any ticket.
That week’s winning numbers: 3, 21, 22, 23, 24 and [something, I forget, but not 20 or 33]
I won a hundred bucks. First time ever. 
2^0=1. I know it’s true, it seems like it ought to be 0. Always has, every since I learned this as a wee lad.
Quantum ANYTHING, dude. Every shred of information I read about it (to the extent that I can grok it at all) is just tooooooooo weird to wrap the sclerotic old brain around. Most of all, ESPECIALLY the Quantum Eraser stuff.
And what is more wireless than Quantum Entanglement? Now that’s hard to grok. Even Albert Einstein said so:
(Anything other than zero)^0 = 1.
But 0[sup]0[/sup] = undefined.
And best of all, e^(i pi) = -1 – Try to derive that by any “common-sense” derivation!
ETA: Oh, and let us not forget 0! (zero factorial) = 1
I’m another one who’s superstitious – and it gets worse when it comes to sports. I have certain objects I have to have around me when I’m watching a game. (My Terrible Towel when I’m watching the Steelers, my stuffed penguin when I’m watching the Pens). I get pissed if my mother asks me, “Oh, who’s winning?” SHUT UP!!!
I also won’t wash my Pens jersey when we’re on a winning streak. I think I get worse every season. Help me.
Religion. I know its false, and still feel its wrong.
Good point. 
I think jjimm means he ‘uses’ it to convince himself that it’s pointless buying a ticket.