https://www.youtube.com/watch?v=uepAJ-rqJKA
Watching this video sparked this question for me.
Using their list, here is how I would rank why I play the game, in order of most to least:
1 discovery 2 fellowship 3 expression 4 competition 5 challenge 6 abnegation 7 sense pleasure 8 fantasy 9 narrative
Would love to know what your list would be!