I have come across a couple of nasty power- hungry US Customs officers/Border guards, but only at the land borders while driving or biking across.
Never at airports.
The bike one was the worst.
We rolled up on our bikes one Sunday morning about 25 years ago and waited in the road lane.
Not one car or other bike in sight.
The guard shouted out of his booth for us to get off and to go into the office.
We did, and the guard in the office shouted at us to go back outside, as being on bikes we were "vehicles".
We did, and the first guy shouted at us again.
Yes, they both shouted, not spoke normally.
By this time I was steaming, and my friend was having a hard time getting me to keep calm.
The first guy then decided to grill us, and finally let us through for our bike ride.
He was just a wee man in a big jacket who thought he was more important than he was.
The other incident was crossing by car, and there were four of us in our car.
The officer was demanding to know why we were laughing, and he wasn't being nice about it.
He made us tell him exactly what was so funny...I wonder if he thought we were laughing at him...we were not.
I make sure now that I am very subdued and neutral when dealing with US officers, which I have not since 2015.