"Generally speaking, people are stupid."
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I am 59 and feel that people are generally smart. See my tag.
First, let me say that neither one of us takes the "stupid" thing too seriously. And I do agree in principle with your tagline. I guess it comes down to one's relative ability to control the types of people you must interact with on a daily basis. In some lines of work, it's tougher than in others.
By the way, it's veering off a little, but in President Bush's press conference the day after the Republicans lost the election, the press were, as usual, trying to get Bush to denigrate his performance and apologize for living, and he prefaced his reply with, "In this line of work..." That gave me such a chuckle. Like it was any other line of work...