I want to address an idea that this show seems to be pushing a bit far beyond what I consider to be its actual limits, which is that differences are important in a friendship. I assert that friendships are built exclusively on similarities, and that while differences can exist in a friendship, they can only be ignored or removed (by one or both parties changing).
Let me give an example. I work with my friend managing a digital printing department. We first met by chance but quickly found that we had quite a bit in common in the way we process the world around us. When we converse, the topics that last the longest and are the most enjoyable to discuss are those we are both familiar with, or which lead to a mutual understanding. Of course, we’re not the same person; he is somewhat more practically-minded than I am while I tend to be quicker on theoreticals. It happens quite often that one of us will be trying to figure out the best way to organize a workflow – him walking around the room experimenting with the physical materials and me sitting down fiddling with a computer program – and the other will suggest a solution that wasn’t so much overlooked as not thought of in the first place. As time has gone on I’ve tried to learn from his practical approach, which I feel has made a positive difference in my life.
You might think the 2nd half of that last paragraph was me describing a difference that helped strengthen our friendship, but let me point this out: I could have learned a practical approach from any other yobbo with the same tendencies, and I could have just called tech support or gotten outside consultation to get ideas for solving problems with the workflow. In this case I admired my friend so much that I wanted to adopt his characteristics which were different from my own, so I effectively removed some of the differences that used to exist. I consider this a positive effect of the relationship that stemmed from a difference, but ultimately it was caused by an increase of similarities, and wasn't dependent on the fact that we were friends. If I had just taken note of his occasional insights and decided it wasn’t worth the effort to change, I would merely be taking advantage of a different skill set to further my own goals (in this case to help get our work done), much like I would asking for financial advice or getting my motorcycle repaired.
What I like so much about the show’s opener, Friendship is Magic, is that Twilight is initially depicted as being completely uninterested in being friends with the ponies that try to make her acquaintance on account of how different they seem to be from her; in the second half, however, after each one of them demonstrates her core virtue, she smiles in a way that indicates her admiration for their values. The differences that were apparent at the beginning brought them no closer together than the rest of the residents of Ponyville, while the deeper similarities that became apparent over the course of the two-parter ultimately caused the “spark” of friendship.
Again, I’m not saying differences can’t exist in a friendship, or are inherently bad, but I don’t believe they actually contribute to the success of a friendship. Either they cause little enough interference that they can be ignored, or one party changes to be more similar to the other.