By Nina B. Lichtenstein, Special To The Washington Post Last year, I had received a holiday card with a big “Trigger Warning!” on the top of the two-page, single-spaced letter. It read: “This lengthy, old-fashioned, holiday letter may trigger feelings of dismay, disorientation, or dread for those accustomed to getting their news via 140 character tweets, Instachats or Snapograms.