Big Yellow Diary

Why keep a diary? My answer is, because some information may seem unimportant at the time, but later you might need it and forget it. For example, today I plan to visit a friend's house. I’ve been there before, but I just can't remember the exact address. Another example is, there’s someone around me who said something, how can I judge if it’s true or not? One way is to compare it with what they’ve said before and see if there are any contradictions. Without a diary, there's no way to make such a comparison.