Evidently, I am prone to acquire a habit somewhat easily. I do something two or three times and I am ready to do it steadily. I don't overbrush my teeth or eat too much. I have a head that likes to think, to imagine, to find pros and cons to support an idea.
I wouldn't have thought that I could develop a habit of buying too many books. This has gotten to the point where just reading titles gives me a strong lift. Some movie titles can give the idea: "Anybody but you", a romance. "Not you again". I get a laugh. Pavlov says that satisfies my reward center. Repeat.