Probably opening a can of worms.... but I notice you see people saying 'Why do people/the media only talk about the good bits of parenting and never about the negative side?' but it seems to me about an equal number of people saying 'Why do people/the media only talk about the bad sides of parenting but never the good bits?' - which makes me think actually these days we do hear a pretty good balance of stuff about it.
I think there's much less taboo than say, 20 years ago, in talking about the bad bits, which is good and healthy but I think plenty of people still talk about the good parts as well. Maybe it's a glass half full/half empty thing and people feel they hear more of the opposite of their situation.