I wouldn't recommend avoiding traits before trying them out first, as you might be surprised what you enjoy. Every player is different after all and I think it's more fun to have sims with different personalities. I personally love some of the perhaps less popular traits such as Dance Machine, Squeamish, Jealous, Unflirty, Evil, Erratic etc. They can make some really interesting characters and you can 'balance' them out with other CAS/reward traits and character values. As I commented earlier, the only trait I really avoid for sim partners is Hates Children, but that's only because I'm a family player. Saying that, I might still use it at some point for my unplayed sims or if I wanted an evil step-parent character for instance.
