every behavior has a purpose.

If we can blame waking up on the wrong side of the bed for a difficult morning disposition, then my child may have woken up on the wrong side of the universe today.

As parents we must exhibit extra patience or we'll exacerbate the situation, particularly when you have a child with special needs. The experts also tell us to pay attention to antecedents (if I had a mere penny for every time I heard that), & we're told that every behavior has a purpose.

In that case, I will say in my most calm, soft voice...
antecedents can be completely invisible, apparently I'm supposed to be independently wealthy, & my child clearly has a whole lot of f#@%*^g purpose in life.