I'm exhausted

The businessman dragged himself home and barely made it to his chair before he dropped exhausted.
His sympathetic wife was right there with a tall cool drink and a comforting word. "My, you look tired," she said. "You must have had a hard day today. What happened to make you so exhausted?"

"It was terrible," her husband said. "The computer broke down and all of us had to do our own thinking."