We don't have enough mandated holidays.
1.) There should be at least one federal holiday that constructs a three-day weekend each month. I think ideally, any new such holidays should grant the Friday, rather than Monday, as the holiday day - Friday is traditionally the day of dumping problems on someone else, and ruining their weekend. Ruining a three-day weekend in this fashion is especially egregious, and, at least temporarily, the Friday switchup should help to confuse the problem-dumpers.
2.) The informal Thanksgiving and Christmas-New Years week holidays should be formalized - these are already de facto periods of minimal productivity, they might as well be de jure, and we can just focus on being happy/miserable with our families during this period.
3.) In similar fashion, the entire 4th of July week should be declared a holiday, if for no other reason than to resolve issues of confusion on proper conduct when the 4th falls upon inconvenient days like Wednesday, as occurred this year. A week of vacation during the period when there is actually the potential of usable daylight and pleasant weather would have significant mental health implications.
4.) How the freak is voting day not a national holiday already?!?