allrounder99 you are not wrong. I often arrive back in Dubai in the early morning and am never ceased to be amazed how many pilots I hear tripping over their tongues trying to read back simple clearances or asking for requests. I then open my mouth and add to the lack of quality RT, it's really frustrating.
Not a big surprise when you think of it. The University of South Australia found that cognitive information processing ability after 18 hours of being awake, was the same as someone at the legal limit for blood alcohol in most Euro countries, while being awake for 24 hours put their processing ability at nearly double the legal limit.
Throw in hypoxia and the dehydrated state that is fundamental to sitting in a pressurized airliner, add a dash of jet lag and you end up with a very reduced mental capacity.