Tired people tend to get stuck and cannot shift well when faced with the unexpected.
Sleep deprived people may perform expected tasks well. Yet, when they are faced with unexpected events their reaction times are significantly impaired. These impairments can lead to safety errors and accidents. Early research has found sleep loss or disruptions to circadian rhythms (shift changes, jet lag) make it difficult to switch from proactive control to reactive control. Tired people lose cognitive flexibility.
PositiveTip: Get adequate sleep to maintain cognitive effectiveness.