My theory is that my kids say "I'm too tired" when what they really mean is "I didn't feel like doing it, please leave me alone about it." I don't know if Cordelia does that too, but at least with my kids "too tired" usually doesn't actually mean "too tired."

Would you like me to come by and help with the laundry? I need to run some other errands first, but could probably come help later if you want help.