Of late I have become interested in how birth order affects the interactions between human beings. Of course, one's place in the birth order "pecking order" does not account fully for an individual's personality, but it does explain many things as we interact with one another. As a pastor, I have found it helpful to know a person's birth order as I work in ministry with her or him (not that I am always asking).
Here's a list from Parenthood.com of birth order characteristics. Does your birth order explain much about your personality or are there other factors that have pushed you outside the "birth order box"?
Doesn't make waves
Follows parents' wishes
Highly attuned to needs of others
Doesn't like to follow authority
Few expectations of self