I don't have any consistent experience with airport staff generally, but when it comes to immigration workers, I've found most countries to be staffed by pleasa

I don't have any consistent experience with airport staff generally, but when it comes to immigration workers, I've found most countries to be staffed by pleasant, cheerful people, including in the USA. The one curious exception has been the UK, where I've had a solid run of miserable sods who don't seem to appreciate that anyone would want to visit their country.