you've got another think coming

you've got another think coming

Your expectations are wrong and unreasonable; you better think again. Almost always preceded by "If you think (something)." The phrase is commonly altered as "you've got another thing coming." If you think you can walk in here and just demand a raise, you've got another think coming. If he thinks he can hit it big without paying his dues, he's got another think coming.
See also: another, coming, think

You've got another think coming.

You will have to rethink your position. (The second part of an expression something like, "If you think so-and-so, then you've got another think coming." Also with thing rather than think.) Rachel: If you think I'm going to stand here and listen to your complaining all day, you've got another think coming! Bill: Frankly, I don't care what you do. Andy: If you think you can get away with it, you've got another think coming! Bob: Get away with what? I didn't do anything!
See also: another, coming, think