Zen is really just a reminder to stay alive and be awake. We tend to daydream all the time, speculating and dwelling on the past. Zen practice is about appreciating your life in this moment. If you are truly aware five minutes a day, you’re doing pretty well. We are beset by both the future and the past, but there is no reality apart from the here and the now. So this is a very concise teaching about zazen [sitting meditation], just a reminder to stay alive and be awake. Notice how much you tend to dwell in the past and speculate about the future; it will help you to practice more in this realm of appreciating your life in this moment.
Zenkei Blanche Hartman, Seeds of A Boundless Life