This article from Scientific American describes new research that suggests that if you wear your brain out with executive function activities, you might not want to make any big decisions right away. Even using your executive function for mundane self-control such as avoiding eating foods that are not good for you or following directions that tell you to ignore something that is mildly interesting, may have the effect of making you more susceptible to errors in judgment in subsequent decision-making.
This is news, but it also contains a message as old as human consciousness itself: when you are tired, rest. Forcing yourself to stay awake and perform tasks is a good way to end up making serious mistakes. Of course, taking a rest is often easier said than done. But bear in mind the option of putting off decision-making or major confrontations or attempts to solve seemingly-entrenched problems until you can come at them with a brain fully loaded with fresh executive function capability.
There’s also a wise old message for parents hidden in this research: put your children to bed. Help them settle down when they are tired. Do not try to discipline them or force them to use their executive function skills if it is the end of the day and they are unraveling. Better to let them get a good night’s sleep and start something challenging the next day, even if it means getting up earlier in the morning to make sure something is done for school.