IAD and ORD are the worst I've seen. I would say IAD is worse than ORD. IAD is god awful. If you call ops for anything it either takes 30 minutes or longer or doesn't come at all. Several times they closed us up then walked away and left us there with no push back crew. Called ops like 4 or 5 times and they didn't come for 25 minutes. Wheel chairs either are there waiting or the flight gets delayed bc the passenger waits so long, it delays the out going flight. Oh and forget about them being ready for your arrival.