When we are at work, we think about being at home or somewhere other than work that might resemble play time. When we are at home, we think about the next day's report or meeting at work.

Philosophical Engineering

Often my lack of production is due to my inability to focus on the task at hand (not my focus on my smart phone in my hand), but rather my attention to being fully mindful of what I'm doing. Yes, it's after lunch and the "bell is ready to ring soon to let class out", but when I can focus when it's work and play when it's play, I can never seem to tell the difference apart.