Traits lack depth, how can they solve this?

As everyone already said, I think the main problem is that TS4 traits are very superficial, and only give random emotional moodlets, and nothing more. In TS3 even though sims can have many more traits, I often wish I could add more, because they are fun and complex.
Whereas in TS4, I always struggle to find even one trait I actually want to use. I agree that three traits is not enough but to be completely honest, I don't think I could manage to choose more than that for a sim considering the choice we presently have.
Do I want my sim to get randomly angry, tense, or bored all the time for no reason? I always end up choosing self-assured (because the confident emotion is not as annoying as the others), loves the outdoors, and some other trait that doesn't have too much impact on the emotions. Because honestly, I can't stand having tense sims because they are geeks and didn't play a game for three hours, uncomfortable because they are a foodie and made the horrendous mistake to drink orange juice, or bored because they are an insider or a dance machine and didn't go out today. Traits should make the game more fun, not just be there to annoy the player.
As @Astreon said I think it would be better if the traits had an actual influence on interactions and needs instead of just causing random emotions. Emotions are okay but shouldn't be random. I would like hot-headed sims to get angry at any mean social interaction for instance, and only have negative interractions after that. Not to just be angry all of the sudden in the middle of the afternoon while alone just because.