All that past and all that future weigh down this one little moment here in the present: No wonder the present buckles under the weight. But if all the present has to support is just this one moment, you find that it's capable. It can stand up to whatever weight there is in the moment. So the ability to focus exclusively on what's happening right here, right now is a very useful skill. But it's not the only skill we have to develop while meditating. [...]
Notice the intention behind what you do, watch what you're doing while you're doing it, and then watch for the results. See the connections between the type of intention and the type of results you get, either immediately or over time. That's the skillful use of the past. Unskillful use of the past is when you run back to either getting happy or sad about how things were in the past. Unskillful use of the future is when you start anticipating either with desire or aversion or fear what's going to happen in the future. The one fear that is useful is the fear of the consequences of unskillful actions. That's what keeps you on the path in the present. Another skillful use of the future is your anticipation of how good it's going to be when you finally master this. But still, there's no way you're going to get there unless you follow the steps. So learn to recognize when your mind is referring you to the past or the future: What are skillful ways of bringing in the past or the future, and what are unskillful ways? Sometimes a skillful recollection, say, of the future could be, "Death could come at any time. Are you ready to go? If you're not -- well, what are you doing right now to prepare yourself?" That's using the future as a spur. [...]
So remember that there's more dimension to the practice than just simply the present moment. But the skill of staying in the present moment is one of the more difficult ones to learn, which is why we emphasize it so much. After all, where are you going to observe things if you're not really observant of the present moment? If the lessons you learned in the past aren't working, maybe you weren't really observant then. This is a chance to get more observant, more precise, with each and every breath.