I try not to anthropomorphize any animals; with fish, it's easy not to do so. Generally speaking, I think of them almost as plants more than animals, i.e. if they are healthy they will attempt to reproduce by spawning, giving birth or flowering. If I lose a fish that I have had for years or decades, I am upset, but it simply isn't anywhere near the level of emotion attached to something like a dog or cat. I find it funny when I hear the term "happy" applied to a fish. Come on, people...it's a cold-blooded animal so completely different from us that it's sometimes hard to tell if they are alive or dead! Fishermen know what I mean; when you catch a fish that is destined for the dinnerplate, killing it humanely is a challenge because the accepted methods of distinguishing "living" from "deceased" almost never work. Destroy the brain...cut off the head...and still feel the crushing guilt that comes with beginning the filleting process only to have the dang gills start pumping, or the body start to thrash.
Don't get me started on the betta owners who "know" that their fish "love" them. Oh, please...
I try to provide healthy conditions regarding water quality and food, and also do my best to provide some level of mental stimulation; cover, plants, dither fish, etc. I simply will not have one of those tanks in which the only source of cover is...other fish. But I'm sure that is more important to me than it is to the fish themselves.