Everyone knows a silent loner. Picture the individual who eats alone, never speaks up in a classroom or meeting, and walks the halls or sidewalks seemingly lost in their own thoughts. People who fall into this category are considered introverts. Creative folks often fall into this category. By working alone, they feel as if they accomplish more.
On the other end of the scale are the extroverts. These are the sociable party people. They can be loud and aggressive, often preferring to be center stage even at the cost of hurting others. They seek thrills so as to gain more attention, often at the sake of their own safety and well being. They can be lively conversationalists and enjoy team sports and outdoor activities.
Having both types of characters in a story might set up interesting points of contention. Imagine the introvert wanting silence while the extrovert flits about the office striking up loud conversations.
Your task is to write a story in which these opposites are in the same setting, perhaps assigned to the same team or task. Imagine the conflicts that can arise. The extrovert might believe that her ideas are the only good ones while the introvert might be groaning inside.
Setting is important, but dialogue is critical. Readers are going to want to see and feel what the characters are experiencing. Sensory details of sight and hearing will add important touches to the story.
Have fun with this one.