Why do almost all public holidays turn out crap?

These would include Halloween,Paddy's Day and New Years. Mostly I think it's because they are overhyped and overplanned. It's like you know when you plan a night out for a really long time and then it turns out to be a complete let down and everyone has a bad night but then some random nights that have no planning at all turn out to be the best nights that everyone remembers. Maybe it's also due to the fact that most people drink more on nights such as Halloween than normal nights out, just because it's Halloween or Paddys day. Which leads to drunken messes on the streets, vomit on the streets and all over club toilets and drunken fights.
It's practically compulsory to go out on these nights however I doubt you'll find many peolpe who will have a night to remember because it was a good night.