There is just one instance of this I know of in the game... in my experience sims with the Romantic trait get sad about being cheated on rather than angry. I don't really know why they went with that combination, but it was pretty consistent in my serial romantic sim's experience.
Oh! And hot-headed sims are more likely to get angry at mischief interactions. At least mine really hated prank day in a way I have never seen before.
But generally yes, it would be better if the trait-related moods were not so easily overpowered, and if the gloomy sims got sad and hot-headed got mad and cheerful got happy for a variety of little things that don't have those effects on other sims.
