You’ve got another think/thing coming
If you’re over a certain age, you will probably be familiar with the expression - ‘If that’s what you think, you’ve got another think coming’. But if you’re a bit younger than me, you might well have heard it as - ‘You’ve got another thing coming’, especially if you’re a heavy metal fan. While I can understand that the saying could have changed through mishearing (an eggcorn?), I am puzzled as to how people who use the newer version understand it’s meaning. The original has a perfect logic to it (if not perfect grammar) which seems to me to be completely lost in the newer version.