Here is a list of things that I think everyone should realize, but would probably be healthier and happier without knowing.
1. Just as this comic strip points out, humanity is eventually going to be screwed. Even with technological advances, the we're eventually going to run out of the means to provide for them all, and history is full of examples of what happens when a society runs out of enough food or water. It's not pretty. Of course, if people stopped having so many babies, this could be averted, but that's unlikely. Besides, a negative-growth birth rate brings its own set of problems as a small work working class supports a glut of elderly retirees. Sure, those problems would only last a generations as opposed to bringing on another thousand years of the Dark Ages at best, but, you know, you can't let the economy falter.
2. Stupid people vote.
3. You're probably not that special or important. Seriously, if you aren't the best in the world at something or can't at least compete with someone at that level, you can be replaced.
4. Your kid probably isn't all that special either.
5. Everyone dies in the end.