Recall knowledge is also fun in RP encounters.
There was one scene in a game I ran where the PCs encountered a big strong lizard guy, who was heir to the throne of a lizard tribe. He had been sent to capture the PCs.
A medicine check allowed them to understand that he was some sort of mutant.
A society check allowed them to understand that a lizard his age would normally be chief already. (His responses also suggested that this was a sore spot for him).
A perception check to sense motif revealed that he wasn't really all that gung-ho about capturing the PCs.
Some diplomacy, seduction and persuasion later, and they're working together with him to overthrow his father.