And I'm grateful for these questions, since it presents me an opportunity to paste here my favorite link from my rpwhore friend. Take a look on those questions, think about them a bit. In most cases your ID only tells who are you aligned with, and what you can do rulewise. But thinking about what environment did your character grew up in, where did he learn biotechnology and what he prefers to do on the weekend makes him -real-.
And after you meet someone who leaves the impression that you just spoke a guy from the XXIXth century, you'll see why's everyone so serious.