What if we all actually created a realistic routine so it reflects a healthier and respectful relationship with time that you have developed as a result of underpromising on personal and professional deadlines?

You mean, be honest with how much time we all acutally have in a day? 

The point is to become hypersensitive to how you are utilizing your time by becoming comfortable with the strategy of underpromising so that you can avoid overpromising and over committing yourself.

Instead of planning your day around the best case scenario, plan your day around the worst case scenario. This will provide you with the additional cushion you need, just in case your best laid plans got derailed by life getting in the way. And how often does that happen?