Plainest

One could not look upon his cruel blue eyes, with their drooping, cynical lids, or upon the fierce, aggressive nose and the threatening, deep-lined brow, without reading Nature’s plainest danger-signals.

A dark, gloomy, ill-ventilated room brings depression of spirits, and will make the most elaborate meal unsatisfactory; while the plainest meal may seem almost a feast when served amid attractive surroundings.