Bad Luck Comes in Threes

Our psychology is primed to find things in threes, and then when that third thing happens, we just click off the scanner. And if a fourth piece of misfortune happens shortly after, we're less inclined because we're primed to say, bad luck comes in threes. Some people have linked it back to a three strikes of a match superstition from the mid 18 hundreds. There's another version that says that whoever was third on the match would die by gunshot.