A dad asks questions to his son

Dad: who do u like more, mum or dad?

Little Johnny: both

Dad: Okay, if I go to London and your mum goes to Canada, where will you go?

Little Johnny: Canada

Dad: That shows you love your mum more?

Little Johnny: No, it shows I love Canada more than London

Dad: Okay, if I go to Canada your mum goes to London, where will you go?

Little Johnny: London

Dad: Replied angrily, why?

Little Johnny: why the anger, I chose London because I have been to Canada before

Dad: When did you go to London?

Little Johnny: During the first question