First time
Well, I’ve made my share of novice-GM mistakes thus far, but I also managed to put one over on a player. Go me.
Character mouthed off a bit to Suhayla, who doesn’t appreciate that sort of thing, and then handed his letter of introduction to her. She burned it in front of his face.
Except she didn’t, because Creo Imaginem is a wonderful thing. I did hint, because in these situations one must hint; I gave him Suhayla’s sigil and an utter lack of noise to work with. (Creo Imaginem—illusion magic—gets more difficult the more senses one attempts to involve, logically enough. So since it was an off-the-cuff spell, Suhayla stuck with sight and smell, didn’t bother with sound.) Wasn’t enough. Character bought it as a real fire. Go me.