I feel like this is essentially a very Buddhist approach (I do not disagree with it by the way). If you aren't familiar the very very very basic premise or, hypothesis if you want to look at it that way, of Buddhism is set forth in a list (or maybe a proof! I like this angle!) called the 4 Noble Truths, which you have probably heard summed up even further as "Desire leads to suffering." (In more detail:
(then the religiousy part) 1. All life is inherently unsatisfying (or "suffering" - but that's a strong word and a translated one to boot)
2. We are dissatisfied with our lives because of our expectations for it ("desires") 3. To progress in life/the life cycle/transcend the worldly realm and cycle of reincarnation we must get remove this suffering/craving/expectation that everything will live up to some idea we have in our head (which of course, nothing ever will live up to that)
"Anger" is a strong word but I do believe that a lot of the issues people face, and a lot of the disappointments and perceived failures, is a result of us forming expectations of experiences and things, before we have ever actually maybe even come close to those experiences and things, and becoming attached to these fictional tableaus and results that of course will never materialize in facespace. 4. other stuff other stuff to learn how to do this go here, where "here" is a link to the 8fold path