Why traditions are important

Sarah, Lianna, and Leanne - with their gingerbread houses

There are many ways to think about things.  Take any subject and two different people at random and you will have differences of opinion on a variety of matters.  Most things are not black and white, but rather shades of gray.  These opinions and beliefs come from experiences and education, much of them because of where we grew up - our family.  These beliefs or ways of behaving often are traditional; previous generations did it a certain way, which is why we do it this way today.  Other times such things may be attributed to more ethereal sources - perhaps something gleaned from the internet or because of a random event.
Now, this is important.  Take any one thing and you can probably find people who will be divided on the issue, action, or thought.  There is such diversity in the world that you can find a variety of ideologies supporting or contraindicating anything.  Sometimes, more often than not, these differences are not celebrated but rather debated, even contested.  Such action leads to segregation,  prejudice, and dark emotions.
The other side of that coin though is what we have in common.  Sometimes it may be as thin as our humanity, other times there may be a great many things; we have more in common than in how we differ.  Focusing on the similarities will bring people together, it helps us celebrate the things we collectively agree on.  Focus on the differences and the results are negative; focus on the similarities and the results are positive.
This is where tradition comes in.  It doesn't matter where the tradition comes from.  It could be new or old.  What matters is that it is something that brings people together - it is a way of celebrating what is held in common.  Tradition brings a connection to history, culture, relationship building, and a sense of who someone is.  Memories are built up and you get a connection to family, friends, and community.  It starts as something simple and becomes a tradition which brings people together and celebrates commonalities.
A  good example of this is the tradition my daughter has of building gingerbread houses with her friends.  They have done it for years, whenever they can get together as a group around Christmas time.  It is a new "tradition," one that is built on commonalities.  It is a time to celebrate friendship and Christmas.  They have many differences, but it is not these things that they focus on.  Rather it is the collective beliefs which they jointly use to further their relationships. 
Traditions bring people together.  They allow people to celebrate commonalities and build memories and identity.  Remind people of this when the "Why are we doing this?" whining takes place.  We do this because we love our family; we love our friends.  We do it because this is who we are, and it is who you are.  I know my daughter is happier and has better relationships because of this gingerbread tradition, and when she is older those memories will stay with her and always be a part of who she is.  Celebrate tradition because it is the right thing to do.