Nightmare. Arrived at 0635 for a 0800 NW flight to MDW via DTW- hundreds in line. Self- service kiosk could not provide boarding pass (tried all 3 methods of accessing) with instruction to "see an agent". No airline personnel were available to help passengers (there were many with the same problem with kiosk) only airport personnel ; one of whom just shrugged and walked away. Angry very vocal crowd! We waited 4.5 hours in line obviously missed flight. We were rebooked on a 1425 flight to ORD. Happy to get out of Miami; however since my car was at MDW I had to pay $16. bus fare to MDW and then a 2 hr drive to my home in Michigan. Not one Delta or NW employee could explain the problem. There did not appear to be any weather delays or cancellations posted on monitors. I cannot understand why this airport checks in international passengers as well as domestic passengers in the same lines. Entire families traveling to South America or Asia needed translators which of course meant all others had to wait until a translator could be found. Unbelievable. Another customer in line with me wanted only to check his bag - he had a boarding pass. He said he was at airport at 0616 for 0715 flight and only wanted to check his bag. Curbside checkin was a disaster with long lines and then closing down so passengers then had to go inside and get at end of long long lines there. ORD and MDW work in a professional efficient courteous way. Never will I go near Miami airport again. Sad thing is that no one could or would assist passengers and I truly doubt corporate Delta could care.