It may have been the Hajj terminal - I'm not sure since it was the only time I have ever been there. They blamed the 15 min per person check-in on the computers, but it seemed to be inept check-in agents to me.

You also had groups of people jockeying to be first in line (probably many of whom had never flown before in their lives except for the flight over). Everyone also seemed to have the max baggage allowence.

To put it in perspective though, that was one of the least stressful things that we dealt with during Hajj.