One should always be in love. That is the reason one should never marry
Topic
Habit in this collection is the machinery by which character becomes actual rather than merely intended. Bacon's choose-the-most-useful-life-and-habit-makes-it-agreeable is the foundational claim: we do not choose the pleasant life directly; we choose a practice and discover the pleasure through repetition. Aristotle's we-are-what-we-repeatedly-do has the force of definition. Jefferson's walking-as-exercise illustrates the principle at its most modest: the good life is made of small repeated acts. Goethe on friends and their necessary quirks gives habit its social dimension: the patterns that seem like flaws are part of the person we have grown to know. Disraeli on daily amiability destroying one's nerves is the honest counter: not all habits are voluntary, and some of the most demanding are those imposed by social life. Kipling on youth as a habit she could not part with is the most poignant entry: identity itself can become habitual, persisting past the conditions that created it.
One should always be in love. That is the reason one should never marry
There is no more miserable human being than one in whom nothing is habitual but indecision.
The love of life, then, is an habitual attachment, not an abstract principle.