The American mind can't just comprehend that there's world besides the USA. Australia, Germany, Italy, Norway, Sweden, Finland as many pointed out all have longer routes. Don't let me get started on Russia or we might end up with a new race between the US and Russia trying to come with the longest road.
Another thing the American mind can't just comprehend (about Europe) is how someone can drive across multiple countries without ever stopping on checkpoints/border controls/customs and most of time without even exiting/changing highways.
The American mind can’t just comprehend what it is to send money to a friend in another EU country with just a single number. No 3rd party services, no routing and account numbers, no fees, no banking shenanigans. Simply login into your European bank, type the value and the IBAN and the transfer is done. :)
To your point about driving through countries, we have free travel in between states, and there are a lot of states. So sorta? We only hit border checks going up north to Canada or south to Mexico
Plus the vast majority of the people from the states generally don't drive to other countries, as the US is so large. It's not that we can't imagine it, it's that it's not relevant to our lives in general.