I actually think there are no "wrong" chords if they support the melody. Consider your basic circle of 5th/4ths construct and there are chord relationships shared by multiple keys. There is clearly no rule that restricts you from "borrowing" from other key centers. As for 'substitutions', tritones make anything possible and this is the path to adding 'color' where a standard more predictable chord can sit.

Proof? Joni Mitchell does it. Sting more deliberately so. But the king of this? Stevie Wonder. The more I think on this cat, the more it makes sense why it is easy for him to break the rules: he trusted his ears and it if sounded good, who cares what the rules are. Revisit My Cherie first and then nearly any other of his tunes as he messes with the listener much to their delight.