Scene: I'm at a party where I am having a pretty good time. I'm having a conversation with a group of friends and its going well; I'm enjoying myself. Suddenly, for no particular reason I become incredibly aware of how many people are at this party, how many people are currently in the room, and how loud it is. I begin to feel very disconnected from the entire scene and I excuse myself to the restroom or another quiet, preferably empty room. While alone, I simply sit and allow myself to be aware of the quiet and stillness and gather my thoughts. After what I feel to be an adequate amount of time, I return to the party and continue to have a good time.
What I've just described is what I refer to as "recharging". I am an extremely introverted person, and while I love socializing and being with my friends and doing things with them, I often need to excuse myself to "recharge" and gather my thoughts. I don't only need to recharge during a party, or when there are a lot of people around, sometimes I need to recharge if I've just been (by my standard) extremely social for the day, or I've had a busy few days. Depending on my level of discomfort, my "recharge" period may need to be anywhere from 5 minutes to several hours long. While recharging isn't immediately necessary it is something that makes me feel more comfortable when I begin to get anxious or nervous for seemingly no reason. Many introverted people prefer to be alone most times than with others, I prefer being with people and taking short breaks of being alone.
I know many people scoff at the idea of this kind of thing, and that's fine. I understand, and I envy the fact that you are able to scoff at it. I'm happy for you that you can endlessly socialize and not feel mentally exhausted from it. I wish I had that capability. However, this is a part of who I am, and i don't see that changing any time in the near future.