There is no more regular feature of the Christmas holidays than the anxious balancing act that is brokered by young couples. Shuttling from family to family to insure that everyone's parents are seen and happy requires face-time, logistical planning, and diplomatic skills. If the same genius and energy could be applied elsewhere, there would be peace in the Middle East by now.
The presence of grandchildren exacerbates the pressures. Dueling grandparents are wired to look for leverage and the stakes are high. Generation after generation of young couples have secretly longed for their progeny to reach the age at which they could declare, "The children really need to be in their own home for Christmas." Of course that never really buys them freedom, because what follows are successive waves of incoming grandparents.