Button could quit Honda
"The car was a complete dog and I'm just not interested in racing like this any more," Button told the Mail on Sunday newspaper.
"I remember after Hungary this year wanting to hit something. I'd won that same race 12 months previously and now I was there sitting in something which was undriveable."
"I have to start winning and if I don't then I have to be ruthless," he declared. "There's an option in my contract which means we can all sit down and discuss the future at the end of the season.
"If things don't work out, that's exactly what I'll be doing," he said of the year ahead.
"I'm not saying I expect to win the world title, but I do expect a dramatic improvement.
"I can't be bothered with working my nuts off and qualifying fourteenth any more. It's making me unhappy," Button added.