The happiness of your life depends upon the quality of your thoughts: therefore, guard accordingly, and take care that you entertain no notions unsuitable to virtue and reasonable nature.
— Marcus Aurelius

Pleasure that is obtained by unreasonable and unsuitable cost, must always end in pain.
Samuel Johnson unsuited quote

A true personality . . . is like a robust organism that, with unconscious sureness, seeks out and digests the nourishment appropriate to it and vigorously rejects that which is unsuitable.
— Gustav Mahler

Of all the various kinds of sexual intercourse, this has the least to recommend it. As an amusement, it is too fleeting; as an occupation, it is too wearing; as a public exhibition, there is no money in it. It is unsuited to the drawing room, and in the most cultured society it has long been banished from the social board. It has at last, in our day of progress and improvement, been degraded to brotherhood with flatulence. Among the best bred, these two arts are now indulged only in private--- though by consent of the whole company, when only males are present, it is still permissible, in good society, to remove the embargo on the fundamental sigh.
— Mark Twain

There exist certain individuals who are, by nature, given purely to contemplation and are utterly unsuited to action, and who, nevertheless, under a mysterious and unknown impulse, sometimes act with a speed which they themselves would have thought beyond them.
— unsuited quotation by Charles Baudelaire