We all have our own duty to our family members. And no matter how busy we are or how exhausted, we need to complete our duty. Because of our delay or mistake other family member may suffer. And then you will feel it's better to have headache or sleepiness time rather to see others are suffering where you might help.
I think this mentality keeps a mom working all day and night... where she always feels she should do more for her family to make it better.