Hi. When I play with a family, each time the sim ages up and the "choose a new trait" popup comes up, I always let the game choose for me and hit the "random" button. Since I don't have a storyli...
First trait is based on traits they had as infant/toddler, the rest are randomized. If what pops up is stupid like dance machine or whatever the get together club-based trait is, randomize again.