Interesting take on the selfish nature of people. Perhaps you are correct on this one. And yes, I agree, we do things not just because we consciously do those, like helping someone to take that can from the upper shelves, or crossing the road examples you gave. Subconscious plays a role, for sure.

I very much agree with you the things we do, including reading posts and commenting, engaging here on HIVE, should only be executed when one likes to do so. Perhaps indeed for one of the three reasons you gave: emotional, practical, or mental reward. Otherwise, it becomes a job aiming to collect money. The latter is for most a bummer, since the money part will never offset the amount of time spent, not for people living in the richer countries at least.

I'll have to dig deeper into life 'theories' such as Buddhism. At its core, Buddhism says: Help others, to gain happiness in our own life. Based on what you say, and the examples you gave, I am curious if the two are the same, or Buddhism may give a counterargument to what you bring forward. Did you ever try and figure this out?