"One of those deep observations"

With reflections of this nature [Miss Bridget] usually, as has been hinted, accompanied every act of compliance with her brother's inclinations; and surely nothing could more contribute to heighten the merit of this compliance than a declaration that she knew, at the same time, the folly and unreasonableness of those inclinations to which she submitted. Tacit obedience implies no force upon the will, and consequently may be easily, and without any pains, preserved; but when a wife, a child, a relation, or a friend, performs what we desire, with grumbling and reluctance, with expressions of dislike and dissatisfaction, the manifest difficulty which they undergo must greatly enhance the obligation.

As this is one of those deep observations which very few readers can be supposed capable of making themselves, I have thought proper to lend them my assistance; but this is a favour rarely to be expected in the course of my work. Indeed, I shall seldom or never so indulge him, unless in such instances as this, where nothing but the inspiration with which we writers are gifted, can possibly enable any one to make
the discovery.

(Henry Fielding, Tom Jones, I v)