If not the greatest, this has to be one of the greatest you'll see this year. The most recent issue of Comic Yurihime offered up a doozy of a printing error.
On page 173, one of the characters of Yuru Yuri exclaimed, "These clothes are so cute", while reading the magazine. The magazine was blank. It contents? Blank.
This isn't some sort of commentary on her sanity. Rather, this is the result of a printing blunder. The manga apologised for the oversight, blaming poor copyediting for the mistake. It also posted the correct images on its website.
Looking at a fashion magazine and saying something is cute is just dull. Looking at a blank mag and saying that? This mistake makes the manga far more interesting.
「コミック百合姫」5月号 『ゆるゆり』 にてまさかの印刷ミスｗｗｗｗ [オレ的ゲーム速報＠ノンアフィ]