Daddy Issues. Poverty.
Etc. etc.
Lady GaGa and Ayumi both are manufactured products and divas. The only thing that Lady GaGa can do that others can't is make people talk about her, because the more they talk, the most famous she is. So she purposely provokes just to get a reaction. She is succesful only in the way that she tricks people into believing she is artistic and sincere, and seem to ignore all the evidence that she is, in fact, manufactured.
If Lady GaGa is artistic, she is only artistic in the most shallow, unintelligent, manufactured, mainstream fashion.
For example, the whole media frenzy. The "hermaphrodite" thing, controversial videos, constant sexualizing. Oh shit, it's MADONNA. Remember her metal book about sex?
So the best bet is, in fact, NOT to talk about Lady GaGa. IRL, if anyone brings up Lady GaGa I immediately disengage from the conversation.
Her albums seem to mock fame, but she seems more fame-hungry than most pop stars.

GaGa wrote a song for Heidi Montag, that got horrible reviews (before GaGa was famous). Then, when GaGa recorded her own version of the EXACT SAME SONG, online reviews LOVED it. Holy shit, GaGa, you sure cast a spell.

tl;dr Lady GaGa is not an artist or artistic. She is a manufactured diva pop star, JUST LIKE Ayumi Hamasaki.