A good invention is typically characterized by its usefulness to a broad audience, rather than just a niche group. While many successful inventions are patented, not all are, and some impactful innovations can exist without financial gain, such as the World Wide Web. The potential for profitability is often seen as a marker of a good invention, but it is not the sole criterion. The discussion emphasizes the need for a clear definition of what constitutes a "good" invention, which may vary based on individual perspectives. Ultimately, the criteria for a good invention encompass utility, accessibility, and potential for widespread impact.