When you allow time to pass in an unproductive manner, it is wasted.  In essence by devoting our time to a useless activity we expend efforts for no result.

Of course devoting your time to doing nothing does not expend effort but also, seemingly, does not produce results.  While the value of doing nothing could be arguable, I would suggest it is not necessarily wasted time.e

With Intent

On occasion we may purposefully waste time, (i.e., work more slowly and inefficiently) just to fill the time and stave off boredom somewhat.

In the long term staving off boredom through wasting time resolves little.  It does not address the root issue and so just provides

Taking initiative, finding productive and worthwhile ways to expend our free or unassigned time is actually far more beneficial than wasting time, albeit requiring greater effort.

Boredom is a Choice

Staving off boredom through time wasting does not address the root issue and so does not resolve the problem .  This approach provides temporary relief at best.

Whatever is the meaning of life it is certain life without purpose has little value and so little meaning.  Wasted time is an acknowledgement of a lack of purpose.

Being bereft of immediate goals we simply decide to coast until provided an opportunity not too.  Why not create our own opportunity.

Reason for Being

We can always find a purpose and expend effort to achieve it.  Wasting time is a choice, not something thrust on us for which we have no control.

At any given time, determine your reason for being and act.  Only you can make this choice.