Any individual fan (note: never the entire fan base) who has been following a team loyally for a long time while never experiencing their team be successful. The teams that haven't won in a very long time will have lots of long-suffering fans. Chicago and L.A. are examples of teams that prior to their recent wins had had lots of fans go decades without success.
A few other teams have sort of brought it on themselves from fan attitude perspective, but I'll be civil and not name names.
If you're saying Leaf fans deserve it you'd be 100% wrong. You just don't know the history of the team.
Little boys were molested and a couple killed themselves in the gardens because of our owner. He used the cup banners as drop-cloths for painting in the arena. He was convicted 40 times as a felon. And yet they sold out every game.