Medicine is a career NOT a job. You either like what you're doing or you don't. Shoveling ****, that's a job. Trash collection is a job. Medicine is a career. Law also. Career implies you're doing it because you want more than just the paycheck, etc but because you have passion for it.
I get it, who doesn't want to work less and still earn a good pay. I also agree that you should come into medical school with some type of goal. However, the OP comes of as "I want to do these specialties or nothing at all" and that just screams closed-mindedness. To refuse to consider anything else is unfortunate at best. Furthermore, the specialties with good hours are highly competitive, what happens if OP can't do those? Just quit because the hours are too long? That being said, medicine should not be your entire life but it will be a HUGE part of it so you might as well choose something that you actually enjoy doing. Even the most tedious jobs will seem short if you're interested and the easiest will feel long if you can't wait to leave for whatever reason.