The gross body and the mind have, on account of your past Karmas, a tendency to act in a certain way and you act just in accordance with that tendency like a machine. You wrongly impute to yourself the authorship (agency) of these actions and thus make the matters worse. Most of your actions are done more or less automatically.
After a life, all earthly experiences of the mind are sorted and analyzed The essence is taken. The Soul is born again in the physical universe with a new frame and bent of mind according to the nature of the essence extracted in the mental plane.
When you are writing a drama, if sleep comes in, you stop writing and retire to bed. As soon as you get up, you continue to write from where you have left the previous night. Even so, when you take up a new incarnation, you begin to continue the work which you had left unfinished in your previous life in accordance with the current of latent subtle desires of your past life.
Your next life will depend very largely upon the Karma you perform in this birth. There are probably many things which the man of the world does constantly and may do without much harm resulting in any way; if these things were done by those sincere aspirants who are treading the path of Realization, they would be decidedly harmful.
The Chains of Impressions
Mind exercises its rule through Impressions. From Impressions emanate subtle desires like swarms of locusts. From latent subtle desires flows the stream of desire and from enjoyment of objects of desires arises internal craving (intense longing). Internal craving is very powerful. The Impressions are embedded in the mind. There arises a memory of pleasure in the mind. Then the mind thinks of objects. Maya(delusion) has her powerful seat in the imagination. There comes attachment. The mind plans and schemes. You are swayed by the passions. You exert yourself physically to possess those objects and enjoy them. In your efforts, you favor some and disfavor others through like and dislike. You will have to enjoy the fruits of your virtuous and vicious actions. Through this six-spoked wheel of like and dislike, virtue and vice, pleasure and pain, this wheel of birth and death moves on without stopping from beginning-less time.
Thoughts and Desires depend upon Impressions
The nature of desires and thoughts depends upon the nature of your Impressions. If you have good Impressions, you will have good desires and good thoughts and vice versa. Even if you have indulged in vicious actions up to the age of forty, begin practicing virtuous actions such as charity, meditation, service of the poor and the sick, service of elders, etc., from this moment and these Impressions will prompt you to do more virtuous deeds. They will stimulate good desires and noble thoughts.
Mind – Its Mysteries and Control by Sri Swami Sivananda