It does depend on where you enter the country, at least in my experience (UK citizen, have visited a lot both on visa waivers and prior to that on visas, since

It does depend on where you enter the country, at least in my experience (UK citizen, have visited a lot both on visa waivers and prior to that on visas, since the 80s). Every time I've flown into Austin, TX, they've been super-nice. DC likewise. NYC/Newark are brusque but not nasty. San Francisco are scary. Boston on the one time I flew there was just horrendous, though that might have just been one agent who was having a bad day.