This quote implies that extreme quickness or haste can often hinder the process of learning. When we are too quick, we might miss out on crucial details, nuances, and subtleties that are integral to understanding and learning. It suggests that patience, attentiveness, and careful consideration are key to a proper and deep understanding of any subject matter.

The second part of the quote, "With too much thinking to have common thought," suggests that overthinking can lead to a departure from common or conventional thinking. While this can lead to innovative and creative ideas, it can also result in isolation from common understanding and shared perspectives. This might make it challenging for such thinkers to communicate their ideas effectively to others or to relate to the common man’s experiences and perspectives.

Applying this idea to today’s world, we live in an era of instant gratification where we want to learn quickly and think differently. However, this quote reminds us to slow down, to learn thoroughly and deeply, and to balance our unique thoughts with an understanding of common perspectives. This can lead to more holistic personal development.

In terms of personal development, this quote encourages a balance between speed and depth in learning, and between uniqueness and relatability in thinking. It suggests that while it’s important to learn fast in today’s fast-paced world, it’s equally important to learn deeply. Similarly, while it’s important to think differently and uniquely, it’s also crucial to understand and relate to common thoughts and perspectives. This balance can lead to a more rounded personality and a more fulfilling life.