I've been through many airports' passport control and customs. I haven't had a major issue. With the Canadian/US border in NY. Thats another story. I've had to park to the side and go to a different area while the car got searched and they grilled me about everything I did during the weekend [US side]. The Canadian side was worried I'd steal all of their jobs during the weekend. This was all for a quick weekend trip to toronto.
I guess it also depends on the location, I crossed only once, through Vermont
My experiences in airports entering the US (as someone who needs a visa) have been without hassle, thankfully.