A brief note of being careful, followed by a few awkward grunts and a snarky brush-off to negate the original note of affection. All while carefully avoiding eye contact with each other.
That's how my father and I always say goodbye to each other anytime we know we won't be seeing each other for a while.
Most of it is unnecessary - everything has already been communicated long before that second grunt.
I love you too Dad.