Introvert. I get very nervous when there are a lot of people around me.

Also, I'm not pessimistic, just realistic

I'm an introvert forced extrovert given my career choices so far. As for optimistic vs pessimistic. Im both. Some days Im one and others Im, well, the other!

Introvert who can be extrovert when in a forced scenario.

I'm definitely pessimistic, as one of my flaws as a person is believing in myself.

Extroverts hold conversations in real life, not on a video game forum. What did you expect?

I'm an optimist, in the sense that life in itself has value, regardless of success or absence thereof.

I expected most people to be introverts here, if that's what you're asking. Now, you can also have friends and participate on a forum, so it wouldn't be that surprising to find some extroverts on here. However, this thread was made to create discussion and maybe to help the users here better understand each other.

I'm in the middle, but I lean more towards introvert. Oh, and optimist too.

Same. About some things I'm rather pessimistic, about others I'm rather optimistic. I chose 'pessimistic', because I don't have a lot of self confidence (I guess that makes me slightly more pessimistic).

But I do know for sure that I'm more introvert than extrovert.

Probably lean extroverted overall can spend days talking to people about random things, which is my greatest barrier to getting anything done. I'd say I'm a realist overall but I like to also be optimistic.

Definitely an introvert. I spent my teenage years interacting with virtually no one outside of my immediate family. Talking to new people was one of my greatest fears. Now I'm a little better, but I still prefer to spend most of my time alone, and I very rarely approach people in social situations. I also do not and never have had any friends, due to having been both homeschooled and a recluse. 

But yeah I try to lean a little towards optimism.