"Tact is one of the first mental virtues, the absence of it is fatal to the best talent"

In the quote, "Tact is one of the very first psychological virtues, the lack of it is deadly to the best talent", William Gilmore Simms highlights the important significance of tact as a mental and social ability essential for success and effectiveness. Tact, in essence, refers to the ability to interact and engage with others in a sensitive, thoughtful, and perceptive manner. It involves not just what you state, but how and when you say it, ensuring that interactions are smooth and that relationships are preserved positively.

Simms categorizes tact as a "psychological virtue", which highlights its role as a fundamental quality, akin to sincerity, perseverance, or compassion, that forms and enhances one's intellectual and psychological intelligence. This suggests that tact is not merely an optional skill but rather a vital component of efficient communication and interaction. Its position as "one of the first" among virtues implies that it must be focused on and cultivated early on, as it can set the tone for how other virtues and talents are perceived and received by others.

The second part of the quote, "the lack of it is deadly to the best talent", provides a stark warning. Here, Simms argues that no matter how skilled or experienced a person may be, doing not have tact can render those talents inefficient or even harmful. This is since a person who lacks tact might accidentally anger or alienate others, create unneeded conflicts, or fail to appreciate the subtleties of a circumstance, thus weakening their own abilities and accomplishments. In professional and individual circumstances alike, the effectiveness of one's skill is typically contingent not just on the skill itself, but on one's capability to browse social intricacies and foster positive relationships.

In sum, Simms' quote teaches us that tact is a vital quality, without which even the most exceptional talents might falter. It highlights the intricate balance in between raw ability and the art of human interaction, advising us of the profound effect of empathy and understanding in realizing one's potential and ensuring sustained success.