Its juvenile humor doesn't even have the good sense to be controversial and thus worthy of mentioning. Rather, it is simply a humiliating retread of jokes that have been told over and over.
The film doesn't even have enough repsect for itself to establish a working set of rules within the narrative. Supposedly, after attending a workshop with some sort of optimism guru, Carrey's character must say yes to every opportunity presented to him. However, the film plays it as if Carrey instead must obey everything said to him. It's more Ella Enchanted than Liar, Liar. This guru's message was about answering the door when opportunity knocked, not engaging in awkward run/stop maneuvers as a security guard calls to you while you run away with your girlfriend. The premise of the movie created enough problems organically. It didn't need the awkward addition of a stupid plot device to make the movie more inane. It is a paint-by-number comedy that disappoints because after you're done filling it in, you realize all of the lines are in the wrong place.
Yes Man has a decent story, a strong message and serviceable cast. If the people involved with the making of the movie rose to its level, it would have been a a succesful, though predictable comedy. As it is, everyone lowers themselves to Carrey's level and what we get is utter schlock.