Sickeningly sweet cereal, mass marketed to kids through constant bombardment in commercials. Kids statistically hear more cereal peddling commercials than they actually hear their own parents speak. Thus contributing to an epidemic of obesity.
Of course, there are the people with the delusion "when I have a child, that'll never happen." 2 minute long commercial breaks every 4 minutes; 90 seconds of which are advertisements for cereal shaped, artificially sweetened sugar bombs - commercials which are designed by crack teams of the top child psychologists in the world to have as much influence on behavior as the vast majority of parents.
Calls of "the industry should set some voluntary standards to follow" are answered with "OMG! They're suggesting a violation of free speech!" and "Hey parents! The government is saying you're not capable of telling your child what to do! We're just playing these commercials that couldn't possibly influence your kids. "