In my opinion, time is not a fixed construct. From each different perspective, time can seem to slowly advance or advance so quickly that one may say "time flew by today". And even if time seems to creep by slowly, when one thinks of the past, one often concludes that "it seems like yesterday" or "it seems such a long time ago, but yet so close." And why is it that dreams can seem to last for hours, or even days, only to wake up and realize only a half hour has gone by?
Let us look at the mathematical constructs of time for a moment. It takes 60 seconds to make a minute, 60 minutes to make an hour, 24 hours to make a day, and so on. We even need to add a day every 4 years since it takes the earth 365 1/4 days to fully revolve around the sun. These are merely mathematical computations in an effort to measure infinity. Yes the system works and has been effective in measuring out our daily lives, but it is still a mental construct nonetheless. Long ago, a group of people decided that this was the best measurement of time. But what is time? We all have similar ways in which we view time, but it all varies from person to person, and even with one person it varies from perspective to perspective. The past and future are mental constructs in an attempt to further measure time. But the past has already happened, and the future is yet to come, it is only an idea. The only "time" that exists fundamentally is the present moment. We are constantly in the present moment, whether we are aware of it or not. Everything else is just a memory or a thought about an upcoming event or period of time. Perhaps time is just one never ending moment that the mind breaks into different moments to make more sense of it.
Einstein has been noted for one of his theories regarding time. He calculated that if one travels far enough at a fast enough speed, one can bend the space-time continuum and end up in a future "time". Again, that moment of time would still be the present from that particular person's point of view. Now matter how you break it up or define it, one is still in the "present moment" from his or her perspective. This is fascinating because perhaps we can begin to fully realize that happiness is always achieved in the present moment. There is no need to put your happiness on hold due to a perceived future event that you think will bring happiness. That is all an illusion of the mind, for happiness is a state that exists within us at all "times", we just need to fully realize this and let go of all the illusions of the mind which causes us to think that happiness is out of reach until "something happens". Perhaps we can begin to realize that all moments are glorious, and all moments of time can be fully appreciated as the blessings that they truly are.