Once I was told to expect less because having expectations would somehow hurt me. Nevertheless, if you truly understand that nothing is coincident, or that every person is here/there for a reason, or that a leaf falls exactly at the time it is meant to fall; you would see that there is one expectation that you are allowed to have, that is, the expectation that you will get a fair share of every action that you do, and that God will give you exactly what you need. Hence, if there is a need for you to be happy, make others happy, surely, God will make you happy too (or vise versa).