When you write down your thoughts, you're expressing yourself. If you choose to publish your writing or show others, you're sharing your thoughts with others. Your thoughts can help them by being relatable, being inspiring, or being helpful. Even if you choose not to share your writing, you're still helping yourself psychologically because it is healthy to express and explore your thoughts and emotions, and it can help you understand them more once you get them on paper. It also helps you document your thoughts for future use.
First off the Amigo Brothers is just a story and an interloper is a person who becomes involved in a place or situation where they are not wanted or are considered not to belong.