For every human cell in or on the human body there are 10 bug cells. The vast majority of these are good bugs. They do more than just help us digest our food. They interact with our bodies in many ways, most of which we haven't discovered yet. They protect our bodies, which is their ecosytem, much better than we protect our ecosystem. Many of these bugs we get from dirt. Most bad bugs we get from other people. We need more dirt in our lives.