Without time, everything would happen at once in a vast explosion of events and images. Awfully hard to sort out. So time acts as The Universe's way of slowing things down so that they can be experienced, comprehended, enjoyed, weathered, endured, and appreciated. Some would say time is the root cause of suffering for all things come to pass, like the relentlessly turning hands of the clock marching towards The End. Time measures and marks the days, months, and years of each life, it displays evidence of age and aging. Time might appear to be cruel in that regard.

     But think of time like a football game. At kickoff time it's quite exciting, is it not? The players, one of whom is you, comes out upon the field to great fanfare, ready to do battle with the opponent, which could be called 'life'. Promise is in the air, anything can happen and usually does, the possibility for amazing feats is there, along with the equal possibility that tragedy of some sort may occur.
    In the first quarter of life mistakes are made, sloppy play happens all over the field, everybody is jumpy and nervous, but all that is forgiven because it's still early in the game. 
     In the second quarter life begins to get a little more serious. Scoring has most likely occurred on both sides, and the foe's strengths, to greater or lesser degree, have revealed themselves. The foe's weaknesses have also shown themselves, and trickery on both sides has been employed and experienced.  
      Halftime offer a respite. Time is alotted to reflect on what has occurred, take what has been revealed about the opponent into account, and furiously strategize for the remainder of the game.
     The third quarter could be make or break time. By now the team you're on could be marching towards an easy victory, be involved in a pitched battle, or be well on its way to being humiliated in a crushing defeat. 
    The fourth and final quarter could have you resting on the bench victorious while other players take the field (early retirement), or you could be in the thick of it still, riding in an injury cart off the field, or be glumly going through the motions and fervently hoping that the clock would hurry up and tick off those final few minutes.
      All games must come to an end but it was fun while it lasted, wasn't it? You could've watched from the stands but win or lose, it's much more enjoyable to be on the field. (And for the losers, there's always next time) 
     This is what time does, it enables you to test yourself through actual experience and not be fated to learn passively through merely reading about this thing called life. Experience is by far the best teacher.