Don't be fooled

 People like for things to be simple. They try to convince themselves that things can be made simple and they will advice you not to over-complicate them.

It's not their fault. Human beings evolved to be efficient, to consume as little energy possible to achieve their goals. If your image of the world is simple it will be cheap to compute what you should do next.

But the world is not simple just because we want it to be. So don't be fooled that some people behave like they know enough. Most likely they are wrong.

You never know enough.

Learn as much as you can. But the resources are limited. Mostly try to understand what is important.  Choose which do you think that are the important areas and have a deep understanding of the mechanisms that make those subsystems turn. Don't be fooled, this is an over-simplification, mostly we know only in retrospect what was important, but can't do much about that. Luckily, each one of us doing particular choices will cover a lot of ground put together.

Also, they are inter-related so every attempt to isolate the subsystems for ease of analysis is a simplification. But that's the rule of the game: keep the dynamic equilibrium between images that are too simple to be correct and too complicated to be able to work with.

People think that they should "just" aim for happiness. But happiness is a mechanism that makes you feel good when you have the things that you need to survive. And you need to know a lot in order to survive for a long time, not only you but also your species, the ecosystems, the planet. And once you know more you realize how much more is there to know. It is just the never ending story of life, universe and everything.