Why Does Perspective Matter

After reading "This is Water" by David Foster Wallace I was intrigued.  This passage was my favorite out of all the other passages we have read so far in 11 AP English.  I think one of the main reasons for this is because the passage was very straightforward and easy to read while also leaving for a lot to still be analyzed by the reader. Wallace also introduced an interesting topic.  There is a generally accepted saying that everybody is unique and this saying, in most cases, applies heavily to the human mind and consciousness.  Wallace goes in the other direction, saying that no matter what, humans are naturally self centered and mainly only keep themselves in mind when making decisions.  He also goes on to state that this selfishness is "hard-wired into our boards at birth" meaning that we are this way from the very start of our lives.  His reasoning for this claim makes sense though.  Seeing as we as individuals have only seen our world from the perspective of our own body, it makes sense that our decisions would be based solely off of what we know without a doubt to be true and beneficial to us.  Most people will not openly admit that they are self centered because there is a societal stigma based around being self centered, but according to Wallace, the only way to not be in this mindset is to first acknowledge it, and then change how you think about the events you experience.  In the passage Wallace talks about how someone with the self centered perspective might only be able to see their own problems and because of this they have a horrible day and get frustrated.  On the other hand, the consciously shifted perspective acknowledges that the other people that have frustrated him could also be having a just as bad or even worse day, and in doing this the author shows how one could have a happier life overall.  Though one thing that slightly goes against his claim is that a few years after Wallace created this speech, he commit suicide.  In the passage he specifically states that someone of the self centered mindset could be prone to suicide, but if Wallace, who I would assume is going off of his own principles of not being self centered, commit suicide, then how effective is the method that he described in his speech?