Daniel Dennet's books - explains how complex designs like our mind can appear out of very simple rules without the need of a designer or what consciousness basically is - a high level view i.e. how can we understand it in simple terms - or what is the purpose of humor. Some examples: "Darwin's dangerous idea", "From Bacteria to Bach and Back".

>Has anyone had any experience with this before? Yes, I'm having this experience for a couple of years meaning that I'm asking myself if having a decent salary shouldn't imply that the next step is not to try to get more money but to try to be involved in something useful not only for myself but for everyone. As expected, defining "useful for everyone" is difficult. I guess there are many many ways that the world could improve but since there is also the question of our ability to solve some particular difficult issue the world is facing I think we should choose a domain that we think we are good at or at least that we think that we could get good at. I think almost every domain is supposed to address some important need of humanity, it remains to spot a place in the field where you are really solving that need instead of working in the wrong direction. I'm sure you can find in a domain you are familiar with examples of entities that are trying to make profit first of all and only second to think if overall their impact is positive or not. On the other hand, even if they seem less, I hope you would be able to spot the ones who are honest about what they do and they are interested in solving a problem globally. >If yes, then what and how did you make your decision? Unfortunately, I'm also stuck, I'm browsing all kind of science news for some time to try to find the answer and the best thing I came up with is trying to think about big questions like the one you are asking. I didn't find a way of producing and selling or giving for free something useful in this domain (I guess it would be philosophy) anyway I think a problem that should be solved is how to push more people of asking these kind of questions i.e. to think critically if their actions are pushing everything in the right direction or if they should try and do something more useful for them and for others.

To get back to your question, while not being at all an expert in answering this, I would like to say that is a very good question. To follow the example of major figures in the history of science a lot of them besides being very smart people they were very curious and stubborn about some particular field and they were also lucky to be in the position of connecting the dots. So I think you can find something that is useful for humanity that is also related to what you like or would like to do. It will not be obvious for the beginning but sometimes what start as doing something for fun in the spare time can evolve into something important. Of course with the appropriate feedback mechanism of knowing that the end goal is to be useful as a long term project. Trying to trace back why I became a programmer I can only identify the fact that I was amazed to hear about a machine that would be able to play multiple games; then, since I was not so good at games I got bored and tried something else like playing with the other things a computer could do eventually getting to program in high school.

I think you are already on the right track, so good luck!