Way back when people were smart enough to deduce the nature of things without evidence, some of these smart folks believed that the body was made up of 4 humours which caused no end of troubles when they were unbalanced.
I’m pretty sure neither gamers nor RPGs are composed of black bile, yellow bile, blood, & phlegm. However, games have various ingredients and have areas where play naturally winds up focusing. Likewise, RPG participants have a mixture of interests, motivations, and intentions which bring them to the table, and that have them behaving in certain ways.
It may be possible for all of these ingredients and motivations to be in “balance” within a person or within a game, but it seems unlikely and drab. I don’t believe I’ve ever seen balanced humours in a gamer or an RPG.
Just like those crafty ancients divided unbalanced folk into sanguine, choleric, melancholy, & phlegmatic, so we can begin to identify games, systems, & procedures which emphasize some “humours” over others. We can start to see which motivations and intentions within us focus on particular feels, game experiences, and “humours”. We can see what actions and cultures of play naturally emphasize different humours and foster different experiences.
The RPG phenomenon is multifaceted. Humor me, take a look.