When I was little and going into my mother's closet it was experimentation and practice but I had no concept of what transgender meant. Even as I grew older I couldn't bear to fool myself into thinking that this was something remotely legitimate. It was more like a disease.
But once you have accepted yourself strange things start to happen. You begin to be comfortable and appreciate how much of your internal identity this occupies. What you had convinced yourself was only play acting reveals it's true spectrum to you and how much it signifies.
People who aren't trans will dress up for a lark but this is deeply serious for us because it goes to the roots of our personhood. That dress rehearsal of our childhood morphs into the everyday necessity of just being.