Mr. Oatmeal's definition of happiness is almost unrecognizable--some pinnacle of comfort and triumph from which you look down on the unhappy masses? Some cheerful bubbly personality type or mood that he himself has observed but never felt, so therefore by default he is unhappy? I suspect we're confusing 'happy' with 'comfortable' or 'having fun'.
The world offers you comfort. But you were not made for comfort. You were made for greatness. -- Pope Benedict XVIWe are meant to strive, to extend ourselves. With very little tweaking he could have titled it "How to be imperfectly happy" and it would have meant almost exactly the same thing.
In the midst of creating three new people, things get pretty miserable around here. I haven't had a full night's sleep in the 6 months since Bella has been born and I'm not expecting to for at least another 6. This puts me in zombie mode a lot of the time; I can almost feel the brain cells dying. I spend a large amount of time dealing with various bodily fluids, and my normal lack of concern for my appearance has dipped to such a low bar that I probably look like the absolute stereotype of the drab boring SAHM.
But I'm happy. In the midst of the fog, one of these kids will turn around and do something awesome or adorable or hilarious and it's all worth it. Or I'll read an excellent book, discover a perfect sunset or beautiful forest trail. A deep happiness exists underneath the grouchiness, the stress, the exhaustion and constant feeling of failure. I'm doing something worthwhile, meaningful, and it's making me better every day. And if I'm reading him correctly, Mr. Oatmeal is saying the same thing with the opposite words.