Living in the here-and-now gives us the opportunity to experience Presence. When we are preoccupied with what has happened, or with what might happen, we risk missing what IS happening.
Recent studies have shown that the notion we can multitask is largely an illusion created by the fact that our minds can move from one thing to another with amazing speed. The illusion is that we are adept at giving our attention to multiple things simultaneously.
In the spiritual life, we call this having a “monkey mind,” and rather than being a good thing, it is actually a distraction. If we make it a pattern, we live superficially. I agree with Richard Foster when he says, ” Superficiality is the curse of our age.” 
I have learned that it is more difficult to stay focused on one thing than to allow my mind to flit from one thing to another. It has taken spiritual exercise to train myself to concentrate on one thing. And I still find myself “all over the place” much of the time; old patterns are hard to change.
One of my favorite definitions of meditation comes from Hugh of St. Victor, “Piercing the core of a particular truth.” This means making a willful choice and effort to “practice the presence of God” (as Brother Lawrence put it) in relation to a single reality–a “particular truth” to repeat Hugh’s words.
Being present to Presence is rooted in the belief that “every moment is a God moment” and that each moment has more than enough life in it to give us life in some way, if we take the time to notice and receive.
 Richard Foster, ‘Celebration of Discipline’ 40th Anniversary Edition (HarperOne, 2018), 1.