There are significant psychological benefits of letting go. When we let go of painful emotions and focus on the present moment this regulates our feelings more effectively. There is considerable evidence that mindfulness practice improves both mental and physical health.
Letting go is hard because it means that you need to free yourself from some aspects of your past.
Letting go mental exercise
Close your eyes. Take some deep breaths. As you breathe in take energy of expansion and breath out stress and energy of contraction. Breathe in love and breathe out fear. Breathe in freedom and breath out any blocks that you may feel. Breathe in peace and breathe out struggle. Imagine now there is a river in front of you. You can pick any river or any body of water. Picture you are standing there as the river flows past you. Imagine you take off your shoes and put your feet into the river. Up to the ankle. The water is at the perfect temperature. Absolutely comfortable for you. You feel the water overflowing over your feet, your toes, your ankles. Feel the refreshing sensation on your skin. Imagine this river has the power to dissolve whatever you put in it. I now invite you to put anything that you want to cleanse in this river. Imagine yourself offering to this river anything you want to let go of. First think of anything you want to let go in your physical environment. Anything that no longer serves you. Could be the clutter on your desk. Old clothes you no longer wear. Things in your life that are broken. Imagine throwing these things in the river and you do not have to worry about pollution as this river miraculously absorbs those things and transmutes them. So, you are offerings to the river all those things in your physical environment that no longer serve you.
If you want to fly in the sky, you need to leave the earth. If you want to move forward, you need to let go the past that drags you down.