Leaving US they were friendly and helpful as I had a very short time to catch next plane.
Coming back in with customs, etc... no messing around. They meant business.
Definitely need at least 2 hours between flights if you have to do customs. 3 would be better.
Customs people were blatantly rude to the point of abusive with a few people. I didn't experience it but I did observe some pretty "conduct umbecoming" as the publicly humiliated some poor person over and over and over again who clearly didn't speak much English.