It is a good one. I can't claim to have originated it. I heard some other wise person use it in a similar context. It is true, though, not mere sarcasm. It is with love and well wishes that we should part ways with people. Because we know sometimes it's the way it has to be.
A sage once said that the people you met in life, as well as the duration of association, is all predetermined and therefore don't regret when the association comes to an end.
Brock, That's a fatalistic view in line with your views on the issue. I cannot confirm not deny it, although I sure appreciate the end of it: don't regret when the association comes to an end. Associations come, associations go...