I'm glad someone pointed up the differences in the Private Syllabus, esp those turns around a point etc. I have never seen a reasoned discussion of why the US feel its necessary and why the UK feel it isn't.The same applies to joining the pattern at 45 to a downwind v the UK version.
During checkouts in the US, I have been asked to perform a "departure stall" -and needed clarification on what was expected. Some radio phraseology is different (" cleared for takeoff, after departure 22.1", "back-taxi etc)". Some radio discipline is different (when at the hold ready for departure, you don't need to ask to leave the ground freq, you just change to tower). For SEP, in places like Florida and Colorado in summer, you may need to lean the mixture just to taxi to avoid plug flouling. Instructors will not be as fussy about carb heat either.
These and many other differences are small and if you don't conform you won't necesarily get shouted at. To some, they are part of the fun of flying outside the UK but others may worry that they cannot behave as professionally as they are used to back home.