Yosef kept his identity hidden from his brothers for a long time, requiring a lot of resilience and fortitude on his part.  These emotions are expressed in two ways in the text: crying and self-restraint (va-yitapak).  A close reading of the text teaches that there is an ongoing process moving from crying to crying and restraint, and finally onto a forging of restraint that is expressed through crying.  Why does Yosef expose his identity in our parashah and stop restraining himself?