Firestorm
Probably would have worked better if they had just shown it on Hallowe'en, but this Hitchockian episode is like a lot of them from TNG where there's a puzzle for the character to figure out and you are there trying to figure it out at the same time. Always this type of story is a metaphor for the mystery of life and its meaning, as well as developing further the character we are seeing. In this case we learn just how dedicated and determined Alara is to pursue her career, both defying her parents and going to extreme lengths to satisfy herself that she is qualified.
Probably this one could have been made more satisfying by having her solve step-by-step the puzzle, with us along for the ride, but instead the big reveal occurs with both of Alara and us still deeply in the dark. Possibly there wasn't time to do all of this in one episode though.