Our entire lives are happening to us in every moment, and here's why.
No harvest magically sprouts out of the ground. At some point earlier on, in what seemed a small and insignificant act in the moment, we planted seeds. Then we went through all sorts of weather, and then the harvest sprouted out of the ground. What's "past" actually continues to be very present in our experience of life in the moment.
Looking forward to the future, the life we want to create isn't something we're going to start as soon as we get that gym membership - it's something for which we're already tilling the earth and planting seeds, right now. That mistake we made yesterday is fertilizer. The resistance we face today is rain. That bountiful harvest we work for in the "future" guides our experience of the present moment, and is as much a factor as all the "past" cultivation which created our present field full of manure.
Experiencing life in the present moment is essential to our experience of life. And, when we realize that our entire lives - past, present, and future - are all happening simultaneously, in every moment, we gain tremendous agency in creating the life we want to live in. That life is right in front of us, and every decision we face is a new threshold.