Another positive for dementia

Am discovering that arguments with a person who has dementia last just as long as it takes the other person to walk out of the room.  Just been putting a new tv together (courtesy of my mum) and a slight disagreement broke out over the plug of all things.  I decided it was easier to leave him to it so left the room and by the time I went back in 5 minutes later he had no recollection of the difference of opinion and just wanted to show me the tennis.  Who says dementia is all bad?