What do you think would push you to shut down an opportunity?

For me the only thing I can really think of is if it interferes with my morals. We always fantasize about the big opportunity that'll come our way and the riches and spoils that'll come with it. But in our fantasies we lose track of the dark side of what an opportunity might bring. We may love riches but there are things more valuable that chasing riches might transgress. It's an interesting thought. Also an interesting post!