I hear ya re the protits. I find it interesting though if nothing else. re the great terrain v. microbe debate... i have a feeling that it will rage for years. in the end the truth is probably somewhere in the middle.
re stress, i would guess it does long term damage that must be slowly undone (on a mental and physical level). And, when you think about stress, it has another component, that is, its relative to each person. its really how you deal with a situation that determines how it will affect you. what is stressful to some is laughted off by others. its more about how you react to a given situation, or how you don't react-ie-by failing to make changes in life to remove the situation that appears to cause you so much discomfort.
I also deal with this type of issue. I am an attorney and deal with things most people avoid-conflict- every day. I can't change my job now, so i try to change the way i look at it. it has helped much.