Canonically, Homura having this level of faith in Madoka's goodness and thus being completely devoted to doing her part causes a lot of tragedy and strife. Nonetheless, it makes for comedy gold in doujin. (It does make me think how much more fucked up it would get if Madoka weren't, as someone so aptly put it, a dere-dere plushie though. Maybe it'd result in some sort of Oriko–Kirika situation. If I remember that storyline correctly.)