As you start motivating yourself to standup, it doesn’t even occur to you to say bye or anything else. You would have seen no point if you had even thought about it.
Your partner then abruptly stands to leave before you do, grabbing a jacket. However, as the door approaches, your partner begins to slow down before stopping at the door and turning around to give an inflectionless “Bye.” Neither of you feel a thing, positive nor negative.
A few minutes later, you grab your jacket and leave.