Goodbye, even with someone you deeply care about, isn't always sad. At least it isn't only sad. Sometimes it can be like saying hello.

Some of us have said goodbye to children. We bundled them up and coaxed their little eyes and hands to say "bye bye." Soon we waved them off to the neighbor's and school and camp. And at some point along the way we said goodbye to our children for the last time. And we miss our little boys and girls. But we know that had we not done so, we'd never have had the joy of greeting the men and women who share the world with us in a whole new way and go on to invent their own lives.

Sometimes you say goodbye to a friend for the last time. Months or years of meeting and parting, of greetings and leavings gone, you find you've said goodbye to this friendship f…