As physicians, we only see the law suits that come to fruition, and some, if not many, are frivolous. From our perspective it is very easy to just assume a greedy lawyer is behind it all. And sometimes that may be the case, but clearly not always.
Physicians are human, and we do make mistakes. Fortunately they are rare. The fear of lawsuits does likely compel us to practice better medicine, but it DOES drive up costs. As a cardiologist I will order tests that I know will be negative, just because if I don't and something is missed, or even if I can't prove it wasn't present and something goes wrong, then I will be sued. If I were asked by a patient who was paying out of pocket, I would advise them not to get some of the tests I was about to order. I would do the same for my children (actually, I just wouldn't take my children to see a specialist for some of the complaints I see).