In Buddhism can all we percieve / experience b used as teachers?

...I have been working on this one question for a while so can everything we experience in life internally and externally be used as our teachers from a Buddhist point of view?examples.. Anger = powerful emotion active in a person when one is threatened or insulted ,,an injustice over a issue etc also known to protect the persons personality ( possible to say anger is a friend then ! ) anger is an emotion that is automatically generated ,defense mechanism. It is repetitive and has been for x million yrs within the human psyche. We could also say it exists in lower beings birds ,goats , dogs etc so anger could be an important link to other forms of life by now I think you'll get some idea about just one state of mind that's revealed so much ...