I have 3 sons.  When they were young, they offered few challenges except in the area of sleep.  Each of the boys has had some difficulty with having consistent uninterrupted sleep.  And, this meant that Mom and Dad also enjoyed interrupted sleep.  In fact, we found that we were regularly awake during the wee hours of the morning.  This led to a realization sleep affects performance.  Sure, no kidding you say.  Of course, it affects performance.  Well, yes, if you have 3 hours of sleep the night before you are likely not going to be performing at your best the day after.  But, it’s more complicated than that.  If the rhythm of your sleep is consistently altered and you’re losing a little bit of sleep here and there, your performance is also infected.  You may not notice it at first but consider this.  The last few times that you were frustrated consider whether or not you were suffering from some form of fatigue.  Parents see this in terms of how their frustration increases and performance decreases because they simply “haven’t had a good sleep in years”.