Design Fail - hidden in plain view

Invisible to Normals: Glyph: From the Ballad of Halo Jones (2000AD comic strip). Glyph was neutral in many ways (but more importantly?) was completely unmemorable. Like the bleedingly obvious setting staring you in the face but completely invisible until it gets pointed out. Even worse when you repeat the whole process at some point in the distant future, "where was that setting again?" (Ballad of Halo Jones): via Oisin. (Trope link)