Currently, the main cause of obsessive-compulsive disorder hasn't been known, but most cases of obsessive-compulsive disorder are accompanied by extreme phobia toward a certain things. (Such as germs)
People who have extreme phobia of germs can develop an irrational fears that their hands are at risk of germs contamination from touching the objects around them. This cause them to repetitively washing their hands within short period of time.
answer; product market;
answer; they burn down the bushes and trees;