This is a part of one of the first teachings from Buddha after he achieved enlightenment. I believe it somewhat, and I think about it A LOT when it comes to my own expectations of interpersonal relationships. For the most part it helps me to process the interactions I have and occasionally the disappointment I feel. However some things I haven't yet reconciled.
I expected that I should live my life without sexual abuse devastating my family. I don't believe that if I changed this expectation that the suffering and devestation would be altered in any way - or would processing it be any easier.
On a "global" level I have an even more difficult time applying this concept.
I expect that planes will stick to flight plans and not fly into buildings, and it wasn't my expectation that caused the suffering when the twin towers fell.
I expect that every human should have access to clean drinking water, and my expectation doesn't quench the thirst of people all over the world.
I expect that men, women, girls and boys will be respected and not trafficked for slavery and sex - and it's not my expectation that causes the suffering of those taken - and those left behind when loved ones are taken.
I expect that fathers and uncles and brothers and other people in power positions won't rape - and it's not my expectation that causes the suffering those who are being raped.
I have not reached enlightenment apparently. Until such time as I DO become enlightened (what?it could TOTALLY happen!) I will continue to try and use this Buddhist principle as I can to end the cause of my suffering.