Take a moment to consider how many annual traditions you have in your life: your birthday, those of your family and friends, anniversaries, holidays; every day that you mark as an important part in a cycle. Not necessarily the beginning or the end, but rather a celebration of the fact that it still is. When a baby is born we celebrate its life; every year that it is alive we celebrate the fact that it is still alive; if the baby grew up and left a big enough impression on others, we may even celebrate it's life and contributions after it dies.
But are these traditions necessarily important? Is it actually important to wear a poppy on Remembrance Day? Is it necessary to give gifts on Christmas? Do we even have to have a cake on our birthday? When you think about it, these little details aren't really that big of a deal independantly. We perform them to show others that we consider the ideas they represent to be important. We wear a poppy to let others know that we consider the sacrifice of the soldiers in WWII to have been important; getting a present on Christmas tells you that the person who gave it to you is thinking of you and wants you to be happy; cake tastes great and you can't have cake for dessert any night of the week and hope to keep your teeth.
If we stopped celebrating traditions, we could very well forget the behind them. It would still be a new year without "Ol' Angsine" (or however you spell it,) and the Nazis would still have been defeated because of the soldiers of WWII without Remembrance Day; however, without these ceremonies, we might eventually forget to think about these little details.