They say art is in the eye of the beholder; as much as I want to agree, there's still no excuse for 'terrible' typography. Among the worst offenders are the following fonts:
Comic Sans is essentially the stereotype for bad typography and few fonts have ever caused more rage amongst designers. This sort of font is abundant in armchair graphic design - it has no place in the professional realm a is a surefire way to cheapen your brand.
Although this style has its place in design, Curlz MT does not; there are several alternatives available when you're looking for whimsical fonts. Neutral fonts can be used over and over by many brands without consequence, but a very custom/unique font like Curlz MT is used ends up being distracting and ultimately disastrous. (Not unlike the next font, Papyrus).
Like Comic Sans, Papyrus is another running joke amongst designers. At first glance, it's safe to assume Papyrus was created for a specific brand. Alas, Papyrus is used by thousands of companies all over the world. Most designers will say it "jumped the shark" long ago (after its first use), but even non-designers will claim it jumped the shark after it was featured in the ever-so-popular movie Avatar. Avoid this font like the plague.