In terms of decorative function, a wall mirror has the great advantage of accenting some decorative details that may pass unnoticed otherwise. When placed opposite or just above an object that should stand out, a wall mirror makes it a focal point; thus if you have an exquisite rare painting or another artwork, you can emphasize its aesthetic value by the use of a wall mirror hung on the other side of the room facing the object. The shape and the design of the wall mirror should blend well in the overall room decor, since for such occasions it does not have to attract more attention than the item you intend to accent.
Many people wonder whether a decorative wall mirror for almost any room in the house wouldn't be too much. The solution for this dilemma depends on how well the house is decorated and on what effects you actually intended to achieve. Keep in mind, that not all house corners are perfect, and in some cases you may need a small visual trick in order to improve the looks. For instance, a short hall way or a staircase can be aesthetically emphasized by the correct use of a wall mirror that would make it look longer. Sometimes, several mirrors of different sizes are used in combination for more exquisite effects.
The very frame of a wall mirror could play an artistic function in itself, blending in the decor as an artistic item or as a mere additional support. Small frames, classical or traditional frames, custom made frames and many more could all fit well with a wall mirror depending on the specificity of the interior design. Complementation is the keyword here, meaning that the frame detail should not be overlooked as it may enhance or ruin the effects of your decorations.
A wall mirror could create some very dramatic looks particularly at night when the lighting variations are better controlled. Thus, by placing a lamp or a candlelight in front of a mirror, a certain atmosphere can be created in the room, with the entire ambiance being affected in the happiest way possible. All in all, we could definitely draw the line and say that there is not one single case when the use of a wall mirror would seem too much, but on the only condition that good taste be the main decision making principle for the matter.