Neat (vs. Sloppy) Neat, tidy Sims typically enjoy cleaning up the house or grooming themselves in front of a mirror. There's always something to be done around the house and they'll more often than not be found doing it; great for a house, but it can tire Sims out.
With their constant disregard of cleanliness and hygiene, sloppy Sims are content to simply "be." They tend to enjoy just about anything that doesn't require planning or cleaning up on their part.
Outgoing (vs. Shy) Outgoing Sims are likely to jump headfirst into any situation. Charm and confidence are their best traits and when they're in a friendly mood they enjoy group activities most of all. Keep an eye on these characters, though; outgoing Sims can be too brash, and others aren't always so impressed.
Introspective and quiet, shy Sims often think about the world around them and write in their diaries rather than actually interact with anyone. It may be harder to break out of their shells, but if shy Sims take the time to get to know others they'll be delighted by the social world awaiting them.
Active (vs. Lazy) Active Sims are almost always on the move but need a lot of food and sleep to keep up their hectic pace. They're apt to be happiest while breaking a sweat, an exhausting idea to most other Sims. An active Sim will usually get more enjoyment from watching sports on TV than reading a book.
Lazy Sims have been known to veg out on the couch for hours on end, so naturally, they don't need much sleep to sustain their constant lazying. They still enjoy socializing wiht other Sims and can be persuaded to get out of the house once in a while.
Playful (vs. Serious) Playful Sims are more likely to find entertainment and fun in the world around them; they tend to be more curious than any other Sim. They may have a lighthearted nature, but they can wear themselves out with their antics, as well as get on their fellow Sim's nerves.
Serious, quiet, thoughtful Sims are more inclined to enjoy logic puzzles and good conversation, but they don't respond too well to chaos or silly behavior. Repairing broken items or working on an important project can keep serious Sims content.
Nice (vs. Grouchy) Encouraging and generous, nice Sims tend to be easy to get along with and very positive. They'll listen to what other Sims have to say whether it's interesting or not and clean up after dirty roommates. If they don't watch out though, other Sims may take advantage of their good nature.
Grouchy Sims, despite their sour mood, can still be social creatures. They'll probably enjoy teasing a Sim as much as telling a joke. They don't seem to mind when other Sims overreact and they like playing a game as much as anyone else, but be warned: they tend to be sore losers.