Health care is important, and the consequences towards those who lose it can be real. That's why it's important that the president be someone who understands the risks of falling through a safety net, and be committed to protecting access to health care.
Romney's Brain: Holy shit, Obama just accused me of killing this man's wife by giving her cancer!
Fairness in the tax code and new revenue sources to deal with the rising debts will be key issues in this campaign, as evidenced by the wall st protests and the looming fiscal cliff. It is crucial that Romney release his tax returns, not only because it is expected of candidates in general, but it will help the public see where he comes from on these issues. Especially given that Romney's proposals have been independently assessed as "reverse Robin Hood" schemes.
Romney's Brain: They just won't stop these personal attacks! Why can't Obama just focus on the issues and ignore everything I've done or said relating to health care and taxes!?
(Actually, Romney's internal monologue probably doesn't ever say "Holy Shit")