I've recently realized how short the hours at work are. On a workday we tend to think of tons of time available at work, and very little once we get home. However, if you've taken part of a workday to do non-work activity (e.g. read a book) you'll quickly realize how short the at-work time really is.
Each moment matters. The number of times you need to go to the bathroom maters. I'm not saying we should be paranoid about optimal time usage in every moment. In fact, we tend to greatly overestimate the time it takes to do the connective tissue tasks throughout the day. But we should be aware of where time is going at all times and try to not get lulled into a false sense of having lots of time to spare during the day.