I don't know about you but, I slip off into dreamland frequently throughout the day and I really love it when I see other people doing the same. Where are they going? What are they seeing and feeling? Is it similar to mine? Would it be weird to ask? I love a good daydream!
Science, and my experience for myself and with clients, shows we daydream to temporarily escape stress and other emotional pressures. It ignites the communication between the brain's "default network" - where our mental activity activates - and the "executive network" - linked with high-level and complex problem-solving.
Until May 2009 it was thought that these two parts of the brain worked on an either-or-basis - when one was activated the other was dormant. And, the less a participant was aware that their mind was wandering the more both networks worked together. By disconnecting from the external world we can focus on our internal mentation... Think Sherlock style, in your own way.
"When you daydream, you may not be achieving your immediate goal – say reading a book or paying attention in class – but your mind may be taking that time to address more important questions in your life, such as advancing your career or personal relationships," - Kalina Christoff
Daydreaming frequency is also linked to how effective our human skills such as; empathy, creativity and memory are. It also decreases blood pressure as it can double up as a form of unguided meditation where we consolidate things we've recently learned.
There are 3 main types of daydreaming and everyone's experience will be unique:
Planning - This wouldn't usually be thought of as daydreaming until we remind ourselves that daydreaming is classified as the consciousness moving away from external stimuli. It also helps to explain why some people, like myself, are great planners but not such great executors of said plans.
Futuristic - I'm sure this one is self-explanatory. This is a really useful daydream as it can help us prepare for future events such as a presentation or life event. It's like test-driving a car out before buying it.
Memorial - One of the best learning techniques is reflection. Thinking about that thing you said over and over may seem like you're beating yourself up but in actual fact, you're processing and learning so that should the same conversation arise in the future you're better prepared. This is the one that also enables stronger empathetic skills as it creates heightened self-awareness of ourselves and others in hindsight.
In essence. When you feel yourself slipping into dreamland it is your brain telling you it needs a break to redirect, process and relax. And, when you see someone else there leave them be, just because you can't see productivity doesn't mean it's not happening.
So, no... Daydreaming is not lazy, it allows our mind to wander so we can take a break from life and shift gears into achieving our goals because we can see them from a different perspective. Even if the subject seems irrelevant, let it happen!