There was an awful lot to be said for familiarity, if you thought about it. It was an extremely underrated virtue, ignorable until the very moment that you were in danger of losing whatever or whoever it was that was familiar.
The quote emphasizes the value of familiarity, suggesting it is often overlooked until it is threatened. This sentiment reflects how people tend to take the comforts of the known—be it relationships, experiences, or environments—for granted until they face the possibility of losing them. Familiarity brings a sense of security that many may not fully appreciate until it is at risk.
The assertion that familiarity is an "underrated virtue" encourages readers to recognize and appreciate the significance of the familiar aspects of their lives. It highlights how these elements contribute to our well-being and stability, urging a greater acknowledgment of their importance before they are potentially lost.