This actually happened, believe it or not. I was going to be away for two days. Boss was booked for four meetings, two on day one, two on day two. I'd told him, I'd emailed him, and I'd printed all the relevant documents and put them on his desk.

Day one he had forgotten about all four appointments. He then promptly booked two new appointments for himself for day two.
Day two he had forgotten about those two appointments as well.

Day three I came back to six angry emails about boss not making appointments or even answering the phone...