This quote suggests that individuals who are solely focused on making money can be dull or uninspiring because their only measure of success or worth is monetary. They lack a diverse range of interests, values, or standards beyond financial gain. This narrow perspective can make them monotonous or uninteresting to be around.

In terms of depth, the quote is critiquing the tendency to reduce everything to a single, materialistic standard, in this case, money. It implies a certain lack of depth or complexity in those who view the world solely through the lens of financial gain. It suggests that there are other, perhaps more meaningful, standards of value that such individuals are ignoring or missing out on.

Applying this idea in today’s world, we might consider the societal emphasis on material wealth and economic success. While financial stability is important, an overemphasis on money can lead to a neglect of other important aspects of life, such as relationships, personal growth, health, or contributing positively to society.

In terms of personal development, this quote might encourage us to diversify our values and interests, and not to focus solely on financial gain. It might prompt us to consider what we truly value in life, what gives our life meaning, and to pursue those things alongside, or even instead of, wealth. It suggests that a richer, more fulfilling life might be found in balancing a range of different values and interests, rather than focusing solely on money-making.