Money is a large incentive, and if it weren't for financial gain things wouldn't have progressed as quickly as they have. But most of the medical procedures we have today were developed to prevent disease, save lives, correct deformities, or otherwise improve the quality of people's lives. Sure, there are some unscrupulous people out there, just out to make a buck, and some incompetent doctors. And the medical industry is not perfect... but to paint everyone involved with the same brush is a bit naive. Nothing is black and white.
And as for strangers making comments, ya gotta learn to be quick with the snappy comebacks!
Man: "Haw big yin, If it rains, you'll be the first to know!"
Me: "If it floods, you'll be the first to drown!"