Have you met a kind of person who is typically reserved or reflective? The fact that they are characterized as an individual whose energy tends to expand through inner reflection and diminish during socially unfamiliar interactions are just something to show the feeling of not belongingness to the people around him or her. These people are called introverts.
Moreover, the introversion that are seen is sort of personality preference. They sometimes have their own world or sometimes make the use of social media as an outlet of their thoughts, ideas, comments and etc. As you go far beyond observations about introverts, they are just a type of person who spends time in reflection, doing such solitary activities because that’s what energizes them.