I sense a "but" coming - You use this when someone seems to be on your side, but you

You use this when someone seems to be on your side, but you can feel them plotting in their head to say 'but' and ruin everything you just said.

My brother said, 'That is the best idea I've ever heard,' and I knew he was about to say 'but I'm still going to take your Xbox.'

My teacher said, 'I like your writing style,' and I knew she was going to say 'but you still didn't do your homework.'

My friend said, 'You're totally right,' and I knew she was about to say 'but I'm still going to tell everyone you're wrong.'