Hi,
This is a very good lesson but quite difficult to practice for many people. I remember emailing this PowerPoint presentation to my employees, and some of them replied back saying, "Please ask my boss to let me put that glass down" :-D. This actually depends entirely on the person. It might sound easy, but it is quite difficult to practice. If you receive regular criticism from your boss, it is very difficult to forget that completely before you fall asleep.
But, as is said, nothing is impossible, and practice can always make a man perfect! 😛