It's not a lifestyle choice any more than you choose to be gay or straight. I actually RECOMMEND watching particular videos on Youtube explaining the experience of a transgender.

In particular, the thing you don't really understand from what I'm reading here is gender dysphoria is a very serious issue for transgenders. It's when the person feels tortured or conflicted from being the physical sex they were born as when they feel that they are actually the opposite gender. In many cases, it's a horrible experience since they don't feel like they fit in at all.

It's one reason why some choose to have sexual reassignment surgery to correct that feeling.