Two things:
1. Women want exactly what they want, exactly when they want it and exactly how they want it.
2. Women HATE rejection in ANY form.
It doesn't matter that your schedule may be packed with essentials. I have female friends who have told me verbatim, when their beau disappoints them, retribution will be steep. "He will pay for that."
I can't tell you how many discussions I've had with ladies when I point out something that they do, yet complain to me about someone else doing THE EXACT SAME THING, yet it is somehow different when it comes to them.