The 3 most relevant lessons I recall, and in my opinion, are the Epistemological World Views, Social Justice (Circle of Faith in Action) and Perception towards other religions.
2 skills that I would say are quite important would be learning to converse with people of different religions and cultures, and learning to read the bible as literature.
I suppose my most significant insight would be related to Social Justice. There truly are a lot of problems in this world. A lot of things wrong with the way our society works. Most of us try our best to help, but something I learned is that everyone should play a part in helping to solve this problem.