Secret Doors Advancing the Plot
Have your players ever used Discern Reality for a secret door and then you used it as a way to advance the story. For example your players are hopelessly lost in a dungeon looking for the Tomb of the Ancient Elder Fish God with a Squid Head. One player searches a dead end for clues and you throw in a secret door just because the players are at the wrong end of the dungeon.
Or any general cool in game moments caused by Discern Reality/You Found A Secret Door!