Who wins?
"kk" vs "bye!!"
"bye!!" wins 88% to 12%. 36 more put them in the same row. From Ways to Say Goodbye in a Text Tier List. Pick a side.
chunky_llama on "kk": kk is cheerful, no notes
ThePenguin on "bye!!": two exclamation marks means they like you
Ways to Say Goodbye in a Text Tier List: the full ranking