We should have had a going-away party for the guy, if only because we live in a small town and shouldn't be embarrassed to meet in the grocery store. In the software development world (where I work) a lot of people get fired or laid off - the work is very demanding and the market is volatile. Being let go is a time when you need support and encouragement, not silence and embarrassment. Those of us who are his former colleagues should have given him a card that said, "We'll miss you! Good luck!"
It's a given that we'll help family and close friends transition through the important events of their lives, but what do we owe to coworkers, neighbors and acquaintances? We pay taxes to finance services for people during times of need, but isn't there also a direct obligation?
A transition that often isn't handled well is moving. Where is the friendly welcome from neighbors? Many people would like to be friendlier with their neighbors, so why don't they reach out? There are probably a number of reasons other than indifference: They don't know if they're intruding; they don't know what to do; they don't feel part of the community themselves and so feel awkward welcoming other people to it.
Death is a transition that we're pretty good at marking, in part because religions have provided ceremonies and conventions that help us know what to do. We all know how funerals work: there is an implicit open invitation and the format is predictable. When the loved one of a friend dies we can attend the funeral, send flowers or a condolence card, or just say, "I'm so sorry for your loss." Would it were always so clear-cut.