What is the Unconscious?
Your Unconscious is mainly made up by your experiences in your past. Also the tendency to not want to feel is a defining part.
Experiences we had
The skills you have are mostly just there, without you being aware where exactly they're coming from. From sitting, writing, talking, to piano playing and driving a car, but also your social skills and emotional reactions, there's quite a lot of them. They all come from your past experiences.
All the experiences you ever had are, in fact, stored in your brain. They are an enormous reservoir of ways to deal with all kinds of situations.
However, it often happens that a person's emotional reactions don't actually help to deal with a situation. This is because as an adult, you still have the imperfect skills of an inexperienced child in you, that are still determining your reactions.
Read more: Your experiences from your past.
Not wanting to feel
The other aspect of your Unconscious is the tendency to not want to feel.
As a child, you can experiences emotions that are kind of heavy, and it can be difficult to deal with these. Because of that, you start doing all kinds of things to not feel things. It is just not really so, that the emotions than actually go away. You may not notice them, but unconsciously, they are still there.
Read more: Not wanting to feel.
Experiences from your past determine how you deal with situations, but this doesn't always work well. These experiences can for example be fears, that are unnecessary for an adult, but nevertheless keep coming up.
This is why it is good to process such experiences from your past. You can do this, by making unconscious experiences conscious. You look for them in yourself, and you consciously feel them.
Read more: Processing.