That's a very thought-provoking question. In my opinion, whether personal happiness is a good thing or not depends on the individual. Personal happiness is a good thing as long as it's something someone wants to do and it doesn't exploit others. The arsonist situation you brought up is a great example of how one's personal happiness isn't a good thing. On the other hand, the pizza delivery driver may be happy with his life because he likes delivering pizzas and has a great relationship with his parents. At least he has a job and isn't mooching off of them. The flip side could be that he's miserable because his parents treat him like their personal slave, and he can't afford to leave because they're taking some of his money for their uses.
The accountant may be happy because he enjoys his occupation and his family. On the other hand, he may feel depressed because he became an accountant and got married only because he felt he had to as a result of family/society pressure. Maybe he wants to stay single and travel the world, but is afraid to disappoint his parents.
Personally, I don't like it when people tell me what I should and shouldn't value. I keep to myself a lot, and that sometimes attracts the attention of know-it-all, busybody extroverts who pry into my life and tell me to be more outgoing. It's not like I tell them to be less social and stay home and read a book once in a while. I don't know why some of them feel like they know what's best for me better than I do. How I live isn't harming me or anyone else. Some people are just nosy, control freaks.
All in all, that's my two cents.