When I grow up

Dad: What do you want to do when you grow up? 
Son: ummm.. I think I will work in a shoe shop! 
Dad: Shoe shop? Why? What will you do there? 
Son: I will tell people how shoes are made and what's their shoe size!
Dad: Hmm.. interesting! But the other day you said you want to be a scientist?
Son: Oh yeah.. oh yeah.. I forgot! I will also be a scientist.
Dad: 😮