My experiences with the USA is that it's very much hit & miss. I've had both good and poor even at the same airport of entry. Some of the (few) poor experiences I had were prior to 911, so it's nothing new. With immigration I just remain polite and answer their questions without any attempt at humour (unless of course the immigration guy makes a funny - yes it happens). With the TSA I just grit my teeth and let the imbeciles enjoy their power trip and bark their orders at me.