Having been a practicing clinical psychologist for the past 20+ years, I dread this time of the year in my clinical practice. I see many 'normal' people in tremendous psychological pain and dread, anticipating the family reunions that soon will be occurring.  This happens in both in intact and in blended families and much of my daily dialog is now centering around how survive the holidays. I'm writing today to share some of my thematic insights that hopefully will help people who are struggling with this time of the year in particular and life in general.

1. Our reality (hopes, dreams, wishes) about life and how family 'is,' is often very different from veridical (true) reality.  I call this a 'disconnect.'  Many family disagreements around the holidays are due to an inability to understand that complete family harmony is virtually impossible to achieve in extended families.  To cope, we often suppress, repress, or deny the reality that confronts us during the holiday season.  If you can recognize the belief vs. reality disconnect and understand it, your family get-togethers will be much more pleasant because you can better manage your feelings about those around you, leading to more realistic expectations (and less disappointment).
2. We are essentially flawed, selfish people.  Whether we love someone or not, our needs will always influence, if not actually trump, the needs of those closest to us.  To cope with the holiday drama in your family, be aware of your own selfish needs if you are distressed by the selfishness of others.
3. Love flows downward.  People who know me will laugh at this one because it's a personal belief often shared in clinical practice.  During the holiday season, this downward flow becomes exaggerated.  Parents of grown children can't understand why their children don't express the love and attention to them that they provided and continue to provide while their children were growing up.  (See #2).  My clinical perceptions suggest otherwise.  So accept the notion that your children really do love and care about you (if you are lucky) and appreciate what love they are able to provide rather than being upset about what they cannot provide.
4. There is no such thing as a 'perfect' family.  You never know what goes on in other peoples' homes, no matter what it seems or what you are told.  One of the constant questions in therapy that I encounter is "why do (we) have difficulty when everyone else seems to get along."  I see many of these 'perfect' families in my clinical practice.  So if and when there are disagreements during this holiday season, it is not because your family is better or worse than those around you.
5. The holidays require people to interact in ways that are antithetical to their feelings about other members of their families, such that artificiality and pretense that "all is well" prevails.  This artificiality is exacerbated when having to provide space in your home and entertain visiting relatives whom one is not particularly attached to.  So to the extent possible, plan ahead about the situations you may encounter (for example, the relative who knows everything and insists on telling you about it) and how to let it bounce off you like teflon rather than penetrate your core.
6. Happiness is not a 'given.'  You may have grown up with the notion that as adults we will have life control and be happy.  This is called an 'entitlement fallacy.'  We need to be responsible for and create our own happiness in an imperfect world.  Positive psychology is a paradigm that addresses ways in which belief systems can be changed to focus on the positive rather than the negative.  Instead of dwelling on what you do not have, create a gratitude list or a reality check.  Don't give people the power to make you unhappy.
7. 'Social Comparisons' are stressful.  We all do it.  Sometimes it helps, especially if you're in the 1%; more often it can be damaging because you compare yourself to people who seem 'better off' in a variety of dimensions and you feel worse about yourself and your life.  Work to develop your own internal barometer, vis a vis, your moral compass.  Try to live by that moral compass in all aspects of your life.
8. Treat your family with the same respect and empathy that you would hopefully treat your co-workers.  Try to understand their struggles through their eyes rather than trying to tell them how to make it better.  I confess that often I am less empathic in my home life than in my professional life.  It's something I continue to work on.
9. Blended families can be daunting.  There are multiple players with different baggage who are somehow expected to drop all the psychic injuries that have occurred throughout the year.  To the extent possible, try to think outside your hurts to have a sense of 'evenness' when celebrating as one family unit.  Be considerate of everyone present.  Drop (at least for that day) whatever grudges you may have.  This will often entail a decision to drink moderately, or not at all, to avoid disinhibition of executive control over what you say and how you behave.
10. Remember 'the package.'  I'm not referring to presents.  Whatever family you have is 'the package,' often a mixed bag of positive and negative.   Christmas and Christmas anxiety or disappointments may lead people to think that they would be better off in other relationships than the family that they are now a part of.  Remember that if you leave a relationship that includes children (even grown), 'the package' is lost forever;   The future family photos, the ability and ease of planning family occasions, and the ability for that family to navigate life's future events unimpeded by splitting time with others.  The notion that there is a 'better' family out there is often unrealistic.  That's why the divorce rate of second marriages is close to 60%, and 73% in third marriages.

This may not be the cheery type of thing to blog about during a festive holiday time, and I'm not trying to be a "Scrooge" character who puts coal in people's psychic stockings.  Rather I hope it can be used as a time of reflection and how to manage expectations that are more aligned with reality to avoid disappointment.