Traits are character advantages or flaws which go beyond what skills and attributes can easily define. They allow you to choose quirks, talents, and conditions to further expand and define your character. You can choose as many or as few traits as you want, but they all have a point value; traits which provide an advantage cost points, while those which put your character at a disadvantage refund points.
Choose your traits carefully; while they provide bonuses or penalties to your character rolls, they are intended more to add more dimension to your character, and your roleplay. Don’t take a trait you don’t intend to play.