Yes, learn from the past. Yes, plan for the future. But there are good reasons to prioritize living in the moment:
Living in the moment gives you a fresh start, without your past baggage. If you continue to explore what that terrible person did to you or that big mistake you made, it will more likely infect your present life than help you get past the pain. When I asked my dad, a Holocaust survivor, why he rarely talked about it, he said, “The Nazis took five years from my life. I won’t give them one minute more.”
Living in the moment avoids fearing the future. In the end, all of us die. Indeed, I used to worry a lot about that. Forcing myself to be in the moment has helped me avoid that unhelpful worry.
Living in the moment precludes your being overwhelmed. It’s hard to feel intimidated when you’re contemplating only your next one-second task. In contrast, thinking of all the work ahead can dispirit you into inertia. If you’re at the bottom of a steep hill and look to the top, you might be tempted to not even start up it. But if you just put one foot in front of the other, before long, you’ll likely look back in pleasant surprise at how far you’ve climbed.
Living in the moment maximizes pleasure: You are fully savoring what you're eating, reading, feeling, listening to, experiencing. I recall as a young man, touring Paris. I was so eager to cram the Tuileries into the day, I rushed through the Louvre. Another example: My most pleasurable, memorable eating moments are when I savor every bite, especially the first bite of something. A final example: As I’m writing this article, I take a moment of pleasure with each completed paragraph, when I'm done with the first draft, when I find ways to improve it, when I click, "publish" and see it on PsychologyToday.com, and whenever I get a positive or edifying comment.
"Live in the moment" is a useful four-word philosophy. Alas, it is easier said than done.