It took me years to figure out that when my daughter was tired she was fussy and reactive. She has probably always had some difficulty settling down and going to sleep at night. So in kindergarten she napped when she shouldn't...and later came in from school and went to sleep. Her dad wouldn't enforce a bedtime and usurped my authority be letting her watch tv whenever he handled bedtime. Said he enjoyed her company. She's 15 now and still a meanie when sleep-deprived.