Which is correct: If you think that you’re going out of the house in those ripped jeans, then you have another thing coming or If you think that you’re going out of the house in those ripped jeans, then you have another think coming? If you said the first one, then think again.
The correct phrase is If you think that you’re going out of the house in those ripped jeans, then you have another think coming. It means that you get another crack at coming up with an answer—another think, if you will—since you’ve obviously gotten it very wrong this time around.
The only way that it could be you have another thing coming is if the first part of the sentence said If you thing that you’re going out of the house in those ripped jeans—but then you’d have to stay in anyway for making even less sense.
Sherry
Paul’s book–Literally, the Best Language Book Ever;
Everything Language and Grammar 