Something I've learned in the screenwriting industry is that many sociological high-school films want to comfort the "unpopulars" out there by portraying the "popular, happy, pretty" people as always having some sort of "dark secret that haunts them at night" and while many here want to think that this is real life, that everyone has equal problems, it's not. Most happy people are genuinely happy. It's not that tough to be happy. You most likely to be healthy, you most likely have to be somewhat attractive physically, or you most likely have to be super talented at something you enjoy. Hardly much else to it, and denial won't create it.
For example with me, an uncured growth disorder has caused a few extreme facial deformities that only around %0.5 of female population, and around %5 of the male population has. These few extreme features have caused severe bullying, discrimination, and self-hate in both my female and male "zones". I feel ugly as a male, I feel ugly as a female, and get told it regularly when I try to express either/or gender. I'm proud of most things about my slender body, and I know I'm lucky to have some managable traits like low weight (115lbs) and short stature, but I have a face that is beyond masculine and it really gets me down. It is indeed related to a health issue that should have been corrected, and has required surgery and still does. If I had gotten treatments in the beginning, my face wouldn't have grow to such proportions. To be happy, most people require health, which reflects in physical appearance. Most folks need social acceptance, which usually is based on appearance. Most people need to excel at their talents, which depending on the talent, can be hindered by physical appearance.
I mean, I hark on it alot, but as I've said before, I've rarely ever met an obese, bald, haggard, nasty looking person who could say they were happy without being addicted to World Of Warcraft, without going to church 5 days a week, and without living with their parents who feed them compliments every day. At the end of the day, people can't go out and live a normal life - and keep sane being surrounded by the worlds of sex, music, art, career, gossip, romance, interaction, education, ect ect - without having positive experiences, and most major, longlasting chemical and hormone altering positive experiences in society are, proven by study, traced to sexual and physical attraction, and the reception of it by someone who that person is indeed truly chemically attracted to. (Aka falling in love with the type of guy your mom wants you to have will not make you happy unless it's your upmost heart's desire to make your mom happy and you get turned on by that.)