In my early career, I took it personally whenever someone left the company, especially if I'd hired them. I took any exit to mean the culture was on the brink of failure and it was all my fault.

As I grew up and the org around me grew too, I learned to chill out: to be grateful for the work we did together, to listen critically to their feedback, and to recognize what was and was not in my control. Growth begets change, and exit is healthy. 

Very often I would see them again. Not always as colleagues, but as clients or collaborators of another kind.

I'm eth newbie..just learning
(working on @farcaster)

terminally.online

The company I work for actively encourages us to develop new skills. And this sometimes directly leads to employees departing for a new role at a different company. And yet, the company continues to support us in this way. And when someone leaves, they celebrate their last day of work.

In large part, I think this is because they are just genuinely caring people. But also, like you say, former employees often cross paths again. And this network of current and former employees opens up a lot of opportunities that wouldn't have otherwise existed.