Keeping an idle mind is having no meaningful thought in mind. By its very nature, mind cannot remain empty. If it is not having productive thoughts, then it succumbs to its lower nature and slip into past and future moment to feed themselves with unhealthy thoughts. Hence to live a meaningful life, you have to make your mind engage with the positive and purposeful thought.
Most of the people generally spend their lifetime aimlessly. They do not set a definite goal in their lives. That is why their mind becomes the victim of all sort of vices and wastes their lifetime by having unhealthy thoughts. They tend to regret about past and worry about future and that in turn lead them to remain tense all the time.
The person who has a definite goal for their lives, always keep their mind focused on purposeful thoughts. Their mind does not get affected by negative emotions such as anger, frustration, and jealousy and of the same. They always keep their mind engaged in charting out the road map to realize their short-term as well as long-term goals of their lives sooner than later.
Finally, you should not live your life aimlessly and become the victim of all sort of negative emotions. You must have goal and lead a purposeful life. Make short-term as well as long-term goals in life and systematically work to achieve them step by step. You should also keep a conscious watch on your mind and do not let it drift in unproductive thoughts. Always remember, your mind shapes your life, so make it work for you.