Bad selling means targeting unqualified prospects or lying about outcomes. When someone is truly qualified, you owe them brutal honesty and persistent challenge to their misconceptions so they can make a decision that actually helps them.
What I believe is bad selling is one of two key things. You sell an unqualified prospect, which basically means that you're lying to them, that they're going to get a good result, or that they somehow are qualified when they're really not. If you state the facts and tell the truth and this person is qualified, then you have the ethical obligation to ask as many times as humanly possible and get them to pull their head out of their ass so that they can see the world clearly instead of it being dark and full of shit, which is up their ass, and help them make a decision to help themselves.