Normally, in the moment of doing something, we are not aware of being careless or imprudent. Only after the fact do we realize that what we did was a mistake. "If only I hadn't done that! What a mistake."
Students often have these kinds of feelings after an examination. When they see their score and it is lower than they had hoped, they would start regretting things, such as getting distracted and overlooking a question or not having studied enough before the exam. For instance, because they had not dedicated time to studying, they were not well-prepared going into the exam. When they received the exam, therefore, they became so worried and anxious that their minds went blank.
Why do we have so many regrets in life? It is because at the time of the event, we were not paying attention. As a result, we made mistakes and regrettable consequences followed.
If we continually dwell on our mistakes, however, we would end up getting stuck in the past. The past has already passed. If we keep thinking about it, what happens to right now? We would lose touch with the reality at the present moment.
Besides dwelling on the past, some people's minds are always on the future. They are full of daydreams about their future. They fantasize about becoming a manager of a company and then rising to CEO a few years later. The dream does not stop there. After becoming CEO, next they would construct a new building for the company; after that, they would expand their business overseas. As they dream on about the future, they lose sight of the present moment.
In Buddhism, we talk about the karmic law of cause and effect. If we are not careful at the time of creating a cause, the effect or consequences may not be so desirable. As a result, we end up having regrets. That is why I like to share with people the concept of "taking hold of the present moment." Whatever has happened is already in the past; there is nothing we can do about it. We should instead pay attention to what we are doing now at this present moment. As for our future, it is not possible to know for certain what will happen to us in the future. If we can focus on the present and work hard, do the right things, say the right words, and try to minimize mistakes, we can help to prevent unpleasant outcomes in the future.
Let go of the past and do not daydream about the future. The most important thing is to focus on what we are doing right now and take hold of the present moment.