There are many reasons why a smooth, seamless transition from military life can be impeded, and each individual undergoing transition has particular and unique challenges. A cookie-cutter approach is not applicable.
Throughout the different stages of a military career people transform from individuality to collectivity. They identify with the group and the system provides for them. They become reliant on the support and are secure and confident within it.
Military life provides a secure and stable financial environment, even when operational deployments are dangerous. Service personnel and their families grow with the military culture and have relatively comfortable lives.
When people enter into the military and the culture of collectivity, they begin a socialization process that creates many bonds and friendships that last a lifetime. It's another form of dependence, but as Farley Mowat noted in his book The Regiment, when push comes to shove, people fight for the person beside them. Indeed, these bonds will take them through tough and dangerous times and are long-lasting.
From mental health to severe disability, the nature of issues today also complicates the transition process. With issues of mental health, these are often unseen disabilities and full acceptance of the problem and programs designed to benefit those suffering have yet to be obtained or developed. Stigma is a major factor, although great strides have been made to overcome it. Physical disability is more prevalent now than it has been in previous conflicts. Multiple disabilities combine to create very complicated cases, often involving not only physical but mental health issues, with long-term treatments required even before someone can achieve their new normal. It is at this stage that the military is actively considering terminating future employment.