I think the orderliness of the bus queues at WDW has an inverse relationship with the wait times.
Long wait times = disorderly, impatient mob trying to get on the bus before existing passengers can even exit
Short wait times = orderly, respectful guests waiting in a calm line, allowing all existing passengers to exit calmly
This inverse relationship seems to exist no matter where I was within WDW. I think it's a scientific law.