Writing a diary every day has been a habit of mine for a long time. Recording the events of the day before going to bed at night can help me know where I went wrong today and what I gained.
There were two months in my life when I was happiest, and also when I felt the most painful. I wrote down every bit of the past two months. For others, this may be just a story, but for me, it is an unforgettable memory in my life.
Keeping a diary is also useful. Some things are so bizarre that if you don't record them, over time you will even doubt whether they really happened.