I'm not sure what to make of that article above.
Ophthalmology is pretty cushy, from what I know of it, so not sure why they'd be so unhappy. Also, private practice ortho makes crazy bank...perhaps their call is bad, but I would think it wouldn't be for your average knee or elbow ortho guy in the community. Also, I'd stab myself in the eyeball with a sharp object repeatedly before I'd do geriatrics, but most of the docs who do geriatrics are SO ridiculously nice that they are like Mr Rogers. They probably are so kind hearted they would have 10/10 job satisfaction working in the slums of Calcutta like Mother Theresa. I think you have to take these surveys with a grain of salt in the sense that they reflect not only the effects of the specialties on people but maybe the types of people who choose certain specialties.
That said, if you are going to do surgery then you need to realize that the residency is going to be more hours, and more pressure, than a lot of other fields. There is pressure to perform because you can easily hurt people when you are cutting them open, and there are crappy work hours because you have to learn to operate and so some floor work/patient management as well, while some other specialties can take 1/2 the day to round. Also, most surgical specialties put a lot of stock in their yearly in-service exams, and my impression is this creates more stress. I did internal medicine and at some programs this can be a pretty demanding residency, particulary during intern year, but at least there are certain months that are cushier, and the in-service exam isn't SUCH a big deal, and if you decide you'd rather slack off a bit long term, it's a broad field and once you've done your residency you can find a job where you'll work less hours. Surgeons don't really have as many options (even as attendings) for a cush work schedule, etc. You've got to love what you do it it will probably grind you down rather quickly.