Is it a waste of my time? More importantly, is it a waste of God's time?
See then, that ye walk circumspectly [prudently, warily, as being aware of all circumstances], not as fools, but as wise, redeeming the time, because the days are evil. (Ephesians 5:15-16)
Our time here is short. We have only a brief lifetime in which to fulfil our calling as ambassadors of Christ. Relaxation and rest are not evil in themselves. However, we ought to put our minds to discerning whether we are buying back time for the Lord with our activities, or whether we are frittering it away and wasting it.
Walk in wisdom toward them that are without, redeeming the time. (Colossians 4:5)
Much can be extrapolated from the notion of "walking in wisdom toward them that are without." Suffice to say, when an inordinate amount of time is spent on our desires with little godly profit, we cannot be walking in wisdom either in reference to ourselves, or to them without.