Thanks for input. I totally forgot that here are bad and awful too, not only on the positive side. I agree that puzzle pieces could be colored, it would be easier on the eye than to check those small extra visuals when a connection is positive. Maybe just the extreme versions could be colored someway, as hey are more unique.
In my game a sim will typically have just 7 preferences, 50/50 between likes/dislikes. Most sims will have just a few puzzle icons in their panel, but again, I'd prefer a visual difference to see the extremes, because they might be the most interesting.
I let my sims pick likes/dislike on their birthdays. Child birthday will pick color + 1 liked activity. Teen picks 1 Activity, 1 Sim category, 1 Conservation. Young Adult picks 1 Activity, 1 Sim category, 1 Conservation. There must be a balance between likes/dislikes in each group, meaning if a Teen pick a Liked conversation style, that sim must pick a disliked Conversation style on their YA birthday. There's room for a few exceptions to these rules, though ;)
If a sim has good chemistry with a teen, it might change when that teen reach YA and picks 3 more likes/dislikes. I like this, because also in real life chemistry might fade over time, or you disc over new good connection that you ignored in the past. Relations are not meant to be static... ;)