The inconsistency is the worst but, at least outside America, most customs teams are polite and informative about what is required.
When I travelled to the US, they were constantly annoyed that you didn't have their exact workflow memorized. That still happened when 2 machines, side by side, had different rules!
Oh, and FYI, some places, like Amsterdam, have it FAR more efficient. No emptying bags, no 100ml limits. Bag and jackets go through the x-ray scanner, you go through the nudity scanner. You're done in less than 30 seconds.