We can easily waste energy and time by attempting to do some tasks associated with another task, when we're in the midst of a priority task. We can be diverted when a thought pops into our mind about another piece of work and we then go and do something about it, rather than making a note about what we thought of, to come back to at a later time. It takes about 10-15 minutes to get the brain back into the first task when we divert ourselves from the main task in hand, so it's a sure way to waste lots of time, over a day. Focus on one thing a time and you'll get to the end point quickly.