While fatherhood is a lot of fun, it has to be said that there is one big, constant, nagging downside to being a father: the constant assumptions of people around you that the mother does the work, and the father does the play.
This is particularly annoying to me because my son has been on an extended "Daddy do it!" phase, where the only one of us that he will allow to change his pull-ups, dress or undress him, give him his bath, get up to sit with him when he wakes up in the middle of the night, etc. etc., is me. And even when he isn't being so exclusive, my wife's work takes her away for days, sometimes weeks at a time, and often ties her up at weekends. Overall, I can comfortably say that I've done the majority of feeds, diaper changes, and midnight clean-ups when he throws up on himself over the past four and a half years.
This attitude is pervasive. It's on every baby product, whose packaging and advertising assume that "mom" buys it and uses it. For instance, the pull-ups my son wears at nighttime inform me that they have "easy-open sides for mom." I guess we dads will just have to pull them up over our kids' heads, or something. And a recent free product sample that I requested arrived in an envelope saying "Mom, here's the sample you requested!". The most annoying part of this is that neither one of those statements would in any way be lessened by omitting the reference to "mom". And when was the last time you saw a product advertised as "the taste kids love, the nutrition both parents will approve of"? What, dads don't care if their children eat any old crap?
This attitude extends even to doctors and nurses. The last time I took my son to the doctor, she explained the foul-tasting prescription he'd have to take for the next 10 days, then told me, patronisingly, "being the father can't just be the fun parts of parenting". I restrained myself from responding, primarily because my sick son didn't want to be put down at that moment...
And don't even get me started on the workplace. Here's an ABC News article about Michelle Obama balancing work and family. Where's the piece on Obama? Last time I looked, they're his daughters too... Trust me on this: As a father, nobody will congratulate you on how well you balance work and family. Ever.