I still work hard to know my business. I’m continuously looking for ways to improve all my companies, and I’m always selling. Always.

In this remark Cuban frames entrepreneurship as a perpetual discipline rather than a status conferred by wealth or past wins. “Know my business” stresses ongoing mastery—staying close to operations, markets, and numbers—while “continuously looking for ways to improve” points to iterative optimization across a portfolio, not just a single venture. The closing insistence—“I’m always selling. Always.”—broadens “sales” beyond transactions to the constant persuasion required of leaders: pitching investors, recruiting talent, negotiating partners, and aligning teams and customers around a vision. The quote’s significance lies in its rejection of complacency: success is maintained through relentless learning, refinement, and communication.