you've got another thing coming

you've got another thing coming

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