Introverts are a lot like cactuses. All plants need water and sunlight.
To introverts, water is social interactions, and sunlight is solitude, sunlight, or personal reflection. Just like a cactus is well equipped for a little bit of water and a lot of sunlight, so are introverts well equipped for a little bit of social interaction and a lot of solitude, personal time, and reflection.
Introverts process social interactions over a very long amount of time, getting the very most out of them.

There is too much social interaction for introverts in most of the every day world and not enough time for solitude, alone time or self reflection. There is a place in the world for introverts and I think that they are very important for us to have. This world is not very friendly towards introverts.
Introverts: Find your pocket of sunlight.

Extroverts with introvert friends: Make a pocket of space for the introverts in your life, Please!