GMs definitely need to enforce strict "in character" play, eliminate "across the table" chatter, and by doing so - set the scene for an awesome role-play experience!
Another real world thing. White tea. Can only be picked two days a year, the two days before the flowers blossom. Could be a similiar plant that...is the deadliest poison known, cure known diseases or psychosis, or a potent herb that just tastes awesome.