The act of 'pretending' one of the background characters in a franchise is the main character and trying to forget the 'real' protagonist entirely - especially when they are especially irritating.
The most famous example of 'Final Frantasy': The protagonist from Final Fantasy 12, Vaan was vapid irritating and annoying.
Fran on the other hand was softly spoken, easy on the eyes and later revealed to be an overwhelming badass who totally trumped the bunny-girl image to come off as more of a leader than the protagonist.
Because of this, a lot of players muddled with the Party System so that Fran would appear as the player-character and quietly tried to ignore the existence of Vaan at all.
Compare and contrast with Antonym "Reverse Final Frantasy" in FF7 whereby for a short time, Cid replaced Cloud. Since Cid was a character many players didn't use, they were stuck with a leader-character whom they knew very little about, might not have identified with and certainly hadn't trained with, dramatically weakening their party. This meant lots of players rushed through the plot, craving to get Cloud (their preferred protagonist) back into the game, meaning many players don't remember the story of this part of the game and hesitate to repeat it - sometimes giving up entirely or cheating at this point to get Cloud back in replays.