I see that a few people used the word 'reflect'....and to me, I think a journal is like a mirror. By looking in a mirror, you have to reflect upon yourself. To many people, this is a hard thing to do as things in life aren't perfect and are full of things people don't want to remember. Thus, the reaction would be to try to get away from those problems, and not reflecting upon the past will get you away from it. But, to the original topic, I believe a journal is helpful. In fact, much evidence and experience can show that if you face your problem and it's roots, it'll be much easier to get over with it. By keeping a journal, it will help you to look back at yourself and find knowledge and wisdom from your past experiences. It's also healthy for the brain. So yeah, I think keeping a journal is a very good and healthy thing to do, even though it might be hard to do.