I don't think anyone really minds actually being transgender, per se, but rather the baggage that comes with it. The difficulty in finding help and acceptance due to a long history of stigmatisation is often a hard burden to bear. If, however, you were to measure the relative happiness of the Kathoey or the Hijra of Thailand and India, respectively, to the happiness of those in countries with a history of indoctrination, religious or otherwise, against transgender people, I believe that you would find a correlation between acceptance of one's role in society with the society's acceptance of one's role.
So, hypothetically, if there was a way to afford a perfect "sex change", or perhaps even an imperfect one as we have now, in a society with little or no stigma or derision of/against trans people, then I don't think people would mind, or even think twice, including the trans people involved.
As for finding joy in it? I would say the change and the struggle are what you make of it.