Flip flopper is a social trait in The Sims 3 for Wii. It does not conflict with any traits. It is somewhat similar to the Unstable trait from The Sims 3: Into the Future. When a Sim has this trait, all other traits will change around every 24 hours. The new traits are picked randomly, and are not based on old ones (e.g. a Sim can be neat one day and a slob the next).
This Sim's other Traits can change randomly every day, sometimes for the benefit or the detriment of the day's routine.