Only idiots are always happy. If we see flaws, no matter how small, we try to proceed to the next level by fixing those, there is a brief moment of perceived happiness, but it passes rather quickly, and so cycle continues. What you described is Work-In-Progress. Capitalism is the system that allows that, it allows itself to self-correct.
> Or the people soon displaced by computers and algorithms
Everything that can be automated - should be automated. Humans is a creative reserve that is limited, physical labor needs to become obsolete. Also you don't see any horse carriage operators complaining about being displaced by automotive industry, do you?
> let just not forget that we live in a "society" and not in a box, everyone for themselves
That's right, everyone is not against you, they are just for themselves.