There is enormous supporting evidence that quantity and quality of relationships are directly correlated to happiness
I like people. I have no trouble speaking in public, making new friends, or just engaging in small talk. I enjoy it, so it comes easily.
I simply enjoy being alone more, so I often am, and there is nothing wrong with me for choosing so. Nor is there with any of the other mostly-hermits I know.
The fellow with low self-esteem may have other issues at well, but telling him that the desire for distance from others is innately wrong isn't going to help him become healthier.
I think a lot of people with social anxiety would feel better about themselves if they were, instead, told that it's OK not to be more social than you want to be. There are still behavior rules to be followed; this isn't license to be a jerk. But for many people, they honestly don't do best with too much contact with others, and that is OK.
Other people want me to come mini-golfing. I want to go home and play with my kitten. Other people want me to go to a party. I want to stay home and have a nice bath. Other people want me to come to the beach. I'd rather put on some music and clean my house. Fuck what other people want me to be doing. A 9-5 is as much as I'll let other people control my life and only because that much is necessary until I'm financially independent. I lack the drive to work towards that and am happy with my job, so a 9-5 it is.
I agree with Baeocystin. This sort of "Literally every human must be enjoy being social/around others!" is infuriating at best. No. Not every human who dislikes other people is broken.
I haven't had a friend in 11 years. I haven't bothered looking because I'm content with my life. I do the things I want to do, I game when I want to game, I code when I want to code, I go for walks when I want to go for walks. I don't need to worry about making plans. If I want to go see a movie - I just go. I don't have people trying to call me/text me/email me. It's absolutely wonderful.
I became much happier after I chose to be alone. I realized that I'm not meant to have any close friends. I realized that I'm not a likable person. And I realized that it's totally okay. Even if I change to become a "better" (more likable, able to have more friends) person, I won't like myself. I like myself the way I am. Now, if people don't like me, it's their problem: I took every step possible for us to not interact. If they still seek interaction with me and, after it happens, don't like me, well, it's their problem, they chose to seek interaction with me, not me.
> cynicism
Cynicism is not a feeling. Cynicism is a belief that people always act selfishly. And such a belief has a lot of supporting evidence. Also, cynics are not always negative people. You can be a positive cynic.