Got Caught Laughing At My Own Joke, Worth It Though

My 8yo asked why I was laughing so hard and I told him 'I just came up with a good one.' Told him 'What do you call a sleeping bull? Bulldozer.' I then had to listen to my son explain to me why that joke doesn't make sense because bulldozers are machines not actual bulls. The way he said it was so serious. But I made myself laugh and that's what matters.