EG say a sports team makes a terrible trade and loses their best player. Player then gets injured on new team. That injury doesn't make the decision to trade a good one, but someone claims it was.
I feel like there is a fallacy or a particular type of false logic, with a name, for this... just on the tip of my tongue... but I'm drawing a blank, and so is everyone I've asked (including some English majors).
Some more examples:
Bob is a college student who decides to stay up all night partying even though he has a midterm early the next morning. This is clearly a bad decision. However while at the party he meets Joe. Joe has an idea for a business, and after talking with Bob, the two of them start a business, and make millions of dollars. Just because Bob's decision to party all night resulted in making millions of dollars, it does not make the decision a good one.
George is broke, he has enough money to buy food for the day, but instead George decides to feed his gambling addiction, and buy a lottery ticket. This is clearly a bad decision. However George ends up winning the lottery, and has enough money to never go hungry again. Just because George's decision to buy a lottery ticket instead of food resulted in making millions of dollars, it does not mean that the decision he made to buy the ticket when he did with the knowledge he had was a good decision.
John is late to work, but decides to stop for a nice long breakfast at a diner on the way. This is clearly a bad decision, because his boss has made it clear to him that he will be fired if he is ever late again. While at the diner, John meets Emily. Emily and John fall madly in love with each other, and make each other more happy than either of them could imagine. They live happily ever after. Despite the ultimately positive outcome of John's decision, based on what he knew at the time the decision to stop for breakfast was still a bad decision.