Introverts often spend a lot of time in our head, usually dreaming or thinking. In any type of situation or context, an introvert's mind wanders and I am no exception. Currently writing this article, I am watching "The Martian" starring Matt Damon; therefore most of my daydreams right now are going to a spy-assassin in Middle Earth settings because of the references between "The Martian" and "The Lord of the Rings."
Let's set the scene and dive into the daydream of an introvert. In my daydream, I am a young elf with a bow made from the wood of a Sapling Ent that died. I received the wood as a gift for defending the Sapling Ent from a band of Orcs that somehow managed to control a dozen or so Mirkwood spiders. Although I took out many Orcs and spiders with my willow bow, they eventually overwhelmed me, capturing and holding me for a later time. Before they could start the food preparation, a few hours later three old Ents came to the cries of the dying Sapling. The creatures saw the horrific damage of the Orcs and spiders and my efforts to defeat them. In a gratitude for risking my life, these Ents allowed me to take what was left of their wood and make a bow. This bow was magical, extremely accurate, and could change its own course to hit a target.
Then I snap back to reality as something goes bang in "The Martian." Eventually I drift off into la-la land again thinking about a video game that has settings on Mars. Suffice to say most introverts will experience something like this, some more than others. For example if you're coerced by the family into watching a movie like "the Martian," you'll start thinking about other things on a similar level or with tie-ins. Other introverts will have different levels of what holds their attention and where their minds go.
All introverts daydream about different things. If they like sci-fi. then they likely to daydream of computers, space travel, or nature. Next time if someone asks an introvert a question and they act a little startled, it's likely they just came out of a dream world where they are the hero of their own story.