Comic Sans is dead. Papyrus and Bleeding Cowboys are also dead.
Anyone who knows me knows that I would rather die than use any of the above mentioned fonts-and for good reason. (OK maybe die is a little extreme).
For example, Comic Sans was a font designed to be used in a comic book. That's it. So it has a very light and childish feel to it. And dare I even say, it's a tad juvenile and immature. When I see this font used in a serious setting, it makes me cringe in horror.
Different fonts say different things. Most overused fonts become dead very quickly. Your favorite Microsoft Word font is probably dead. Graphic designers keep up on font trends and knows which fonts are lasting and which are just a phase.
Here are a couple of examples where the right font matters: