A personality that is fake, artificially enhanced and augmented like a body part can be with plastic surgery.
Anyone whom feigns religious piety but in actuality drinks heavily and is a promiscuous skank. (More common amongst woman)
Anyone whom seems inhumanly caring and considerate just to benefit their image.
That girl only talks to band geeks so people will think she is nice and put her on homecoming court, she has a silicone personality.