As an addendum to the traits/flaws issue, if you are unfamiliar with them, They originated in Unearthed Arcana. Traits allow you to swap two roughly equivalent things, such as -1 fort for +1 Will, or boost spot while reducing search, or things like that. Flaws give you a bigger penalty in exchange for an extra feat.
Both things also have homebrewed options out there, as well as several options that were published in Dragon Magazine. If people are forced to roleplay their traits and flaws, it can sometimes be worth it for a wary DM. Many choose not to allow either of them, though most games on these boards allow at least one of each. The maximum is supposed to be 2 of each, as sirpercival stated.