I think I have learnt in therapy too, in a similar way to how Lolagrace describes.
I like the fact that schema therapy is quite structured in some ways. We made flashcards that say "Right now I am feeling X. I need to try to remember Y." etc. Which is actually a very structured way of learning to think differently. It often really annoyed me to be reminded to read the flashcard, because it made me feel stupid, but I had to admit that it really helped me when I did read the flashcard!
But even more than the structured elements like flashcards and evidence lists, the things I have learnt that have been most profound have been to do with my image of myself, and about relationships, and I have learnt them directly from my T and how I relate to T
and how T relates to me. An example is that I used to feel completely terrible if I ever had any kind of argument with someone, and in the past it has meant that I would simply end a friendship because I would never speak to the person again, because I would assume they hated me. But now I don't assume those things any more, and I can hear my T's voice saying "this relationship is more flexible than that, just because I was frustrated, doesn't mean that I think you are bad. It hasn't changed how I see you." I am able to hold on to that and generalise it to the other relationships in my life.
I think I've been very fortunate to have such a good T and that therapy has worked really well for me.