You shouldnt be envious of less intelligent people, as they suffer even more than smart people ; the spend their life wishing they could be in their shoes. In fact everyone suffers most of the time, life being a constant struggle, conflict, a constant search for balance between extremes. The only people i can think of who are truly happy in the west in the sense that they have the more fun most of their lives are rich people who work intensely; being busy , in the flow of a solide daily positive routine is true hapiness, with the help of various expensive drugs. A predictable stable fun life where you control everything, where you dominate everyone. But again, you have to be taught, conditionned, that way from the getgo by your parents. Id go as far to say that everything is conditionned by your upbringings and genetics.
One 's hapiness is often at the expense of others, or by exploiting others weaknesses. But who cares, life is a giant free for all. It's all about killing with a big smile on your face.
We are animals who are conscious of being animals, which means we re still, only, animals. Our only purpose is to dominate, adapt in order to survive until we reproduce and... that's about it. To this day I still strongly stand by this "personal" discovery countless of thinkers made in the past. I guess it's called growing up. You can give it a nice happy spin to the whole thing but it's only if you want to sell books and make money out of it, negating the cold truth; it's all about killing instead of getting killed at all possible and known levels. The only way to escape sadness is to sublimate yourself thru work or creative endeavours, thru positive relationships, to keep busy so you can ignore the reality as long as you can. A reality that will hit you in the face when you re old anyway.