The Only Difference I've Been Able To Spot Between Our Accents Is We Say Costume While Americans Say Costoom - Tumblr Posts

The "Can you tell the difference between an Australian and NZ accent?" made me think of a question to submit:

Can you tell the difference between a generic American accent and a Canadian accent?

Because I genuinely cannot and it absolutely baffles my one american friend but my british friend can't tell the difference either so I wanted to know if we were alone in this.