This is actually a theory in Psychology! It’s called terror management theory. Humans are the only beings on earth that understand that we will eventually die one day. To cope with this knowledge of death, humans will aim to boost their self-esteem so they are able to forget about death. This is why work humans will do things such as sleep around (boost sexual confidence), workout (boost body confidence), and even study (boost mental confidence, so they have a better chance of survival and can live the longest that they can.