I tend to give more than I take, or at least I feel that way.
Most likely though, everything that I give, balances out what I take. In some ways I'm selfish, and in others I'm quite generous. (I haven't killed my brother yet. ;P)
Because I'm naturally such a passive and introverted person, not many people take notice of me until I step up or speak out. In a way, this is how I give peace to all whom rightly deserve it.
On the flip side, I can be quite selfish sometimes, but I'm never unreasonable or extreme in my selfishness.
While I am indeed introverted, at times I do become quite social. Usually this only happens when I'm comfortable with the situation and with those I'm around.