Traits are character personality features. They are general pointers to help the GM award narrative points. Generally, I like to have players pick two traits, one positive and one negative. Traits do not effect character skills or rolls at all, they are primarily there to promote good roleplaying. If a player does something in line with a trait, give them a point!
General Virtues
Humble, Honorable, Honest
Deadly Sin
Greedy, Prideful, Wrathful.
Quirks
Curious, Tinkerer, Sports Fanatic, Collector
Occupations Remember, these don't effect rolls or anything they just inform what kind of person the character is.
Doctor, Scientist, Builder, Detective
I recommend limiting Traits to two maximum. You might get some guy who wants to take like a million of them so they can get narrative points all the time but that really defeats the purpose of them.
The USR (Unbelievably Simple Roleplaying) System belongs to Scott Malthouse and Trollish Delver Games