And bad planning. A lot of my flights have been during the afternoon rush, and they just don't seem to be prepared for it, IME.

If there are weather delays and 5 flights all arrive right around 7:00 PM, I understand that they probably won't have enough staff to process everyone that quickly. But at 4:00 PM, it should be no surprise that there are a lot of int'l arrivals and connections, and there shouldn't be unstaffed immigration booths with several hundred people in line.