It depends on the situation sweatdrop
If I know people where I am, I'm completely, 100% extroverted - but I find it increasingly difficult to bring myself to that point where I actually want to get to know people. Most of my friends happened coincidentally; a lot of them came from my part time job, or because they lived on my floor freshmen year.
From there I would branch out and meet their friends, make new friends, etc. etc. Like I said, as long as someone is there that I am close with, I can be 100%, happy go lucky, hi nice to meet you!
But now that I'm not in those situations anymore, all I want to do is curl up in the corner of the room. I'm not really sure why - I've constantly struggled with holding onto best friends all throughout childhood and graduating college didn't help with that (mostly because it was a forced removal like, look at all these awesome people you cherished for 4 years. Okay poof, you graduated and moved back home, now they're gone).
I think it's just a process and once I finally face the idea that I'll never be going back to that magical land of friends being a 5 minute walk away from my dorm room, I'll be able to put myself out there more and try a lot harder.