External stimulus tends to drain introverts of their energy
Introverts recharge best where there are low levels of external stimuli. They gain energy from spending time alone and are generally comfortable in their own presence. Thinking about a concept/project, listening to music, or reading a book might all sound like great recharging opportunities. As opposed to an extrovert, being alone on the couch for the day will likely find an introvert feeling refreshed and energised. While an introvert may still enjoy socialising, they will generally need time to both prepare for, and recover from a large or noisy event. The busier, louder, and larger the event, the more it drains their energy. It may be fun but they need time to recharge.