I'm probably arguing semantics here, but I would think if you are "comfortable" you should be happy too. I have lived in 4 places over the last 10 or so years. Big city, suburb of same big city, small city, and a remote small town. We have only been truly happy in two of the places. The other two were strictly for career purposes and I will never go back.
Yes if all 4 had been towns of 50,000 scattered throughout the same region/culture /geography (say Mississippi and Tennessee.. Hattiesburg, Tupelo, Jackson TN.. etc) it may not be the case. But the reality is Bend Oregon and Lafayette Louisiana are so completely different even though they are roughly the same size, it's almost guaranteed most people would be much happier in one vs the other.
In a city (1,000,000 + people) you are staring at traffic, high crime, bad public schools, poor air quality, short commutes to great jobs, awesome food options, pro sports, awesome arts/concerts and many other unique pros and cons
In a suburb it's usually moderate congestion, minimal crime, moderate air quality, long commutes, great public schools, chain restaurants out the wahoo, 27 seasons a year of youth sports, and a golf cart to drive around your neighborhood.
The small city (100,000 + people) is a combo of those two.
The small rural town is the true outlier.
All that said, if you take any of those types of places and change the location the culture is completely different. The weather is different. Do you live at the beach, in the mountains, access to outdoor activities, if so what kind?
So yes, in all 4 places we had some level of comfort... Decent/safe home, some disposable income for entertainment, etc. But based on mainly geography, our happiness is 10 fold higher today. If you picked my family up right now and moved us to Atlanta GA or Hattiesburg MS or Plano TX it would be miserable as 17 for us. Literally a prison sentence. That says a lot about us sure, but also the differences in places and the happiness/comfort it affords people with different interests.