“In the realm of this-worldly matters, a person should compare himself to those who are less well-off and to learn how to be satisfied with less.
In the realm of the spirit, by contrast, he should compare himself to his betters, to realize how imperfect he is and to feel the urge to become more holy.
Unfortunately, many people do the opposite.
In regard to this-worldly matters, they compare themselves to those who are better off than they are and as a result grow depressed and envious.
And in the realm of the spirit, they compare themselves to their inferiors, as a result of which they become self-satisfied and dull-hearted.”
From Understanding the Tanya, p. 103 by Rabbi Adin Steinsaltz