It's fake.

The reason why Top Gear UK is so universally loved is not because of the cars, but because of the chemistry. Richard, James and Jeremy act so naturally around each other that it doesn't feel at all scripted or even planned at some points. They actually seem like friends just talking and having adventures. That's why even non car people love it.

Top Gear US feels so overly planned. It doesn't feel at all like they are actual friends, and it seems like every damn line is forced, scripted or both. Besides, they can't even come up with original challenges, jokes or lines.