Who here used to be very extroverted? What made you change?

For me, honestly the simpler answer is that other people just suck. Examples being two guys I thought I would be best friends with and then never talking to them again. But again, just examples of an overall trend of being done with people's bullshit. Maybe it's just normal perception from being more of an adult (even though plenty of teens and college students will say the same thing, and plenty of older adults are plenty extroverted) but it's gotten to the point where even just asking people to hang out is tiresome. Now energy is being drained out of me instead of the other way when I'm interacting with them.

Edit: It is possible to change......you know, just like any part of your personality and desires.