Hey Sarah...I think many people feel it is an inappropriately and overused font. It was used a lot in comic books but then spread to other more serious, professional documents. Many people feel as though content written in CS isn't authored with authority and lacks credibility due to it's "silly" appearance. I have to admit that I feel it has outstayed its welcome, but I am no authority on typeface! I'm loyal to TNR, Helvetica and if I'm feeling dangerous, Garamond!
This topic came up the other day and the response to it seems so overblown. It's a font people. It's a sort of bubbly font, I'll grant you, but just a font. I get that it may not seem the most professional, but I never imagined it would spawn so much vitriol. Google it once. You may be surprised, too.