The real difficulty here isn't forgetting yesterday or tomorrow—it's that our minds use them as escape routes from what's actually happening. When you're sitting across from someone you love, part of your attention is still replaying an argument from last week or rehearsing a conversation you need to have. Buddha isn't simply recommending mindfulness; he's suggesting that regret and anxiety are the same problem wearing different masks, both forms of absence from your own life. Notice how a child playing with blocks needs no reminder to concentrate on the present, yet somewhere between childhood and now, we learned to fracture our attention as a survival mechanism.