"out of sight, out of mind"
Annoyances created by power quality issues fall well into this category. These annoyances take on two forms, those that can be seen, and those that are heard. Few times are they as a result of inefficient operation (a kettle taking longer to boil because the voltage is lower).
Visual annoyances take on two distinct forms, lighting and visual input (computer screen, television set, etc.). Two separate sections have been devoted to this being "Flickering Lights" and "Disturbed Entertainment". The latter section also covering annoyances that affect our other senses and include things like aural e.g. the crackling on a radio.