The ill effects of thought come about when we forget that thought is a function of our consciousness... an ability that we as human beings have. We are the producers of our own thinking.
It seems that we have it backward in our society. We tend to look up to people who are under a great deal of stress, who can handle loads of stress, and those who are under a great deal of pressure.
No one knows exactly where thought comes from, but it can be said that thought comes from the same place as whatever it is that beats our heart... it comes from being alive.