Turning up for briefing forgetting a pen, with an unironed shirt, 6 minutes late, still eating toast. Sitting in a classroom and continuing their conversation when the lecturer walks in rather than shutting up and turning to front.
Professionals have a high attention to detail and an ability to remain focused on the task in hand for long periods of time. I would be very worried if a student aviator could not arrive at class on time, correctly dressed and fed, and with the right equipment for the day, and then be unable to concentrate in class.