The metric for success on <i>any</i> commercial software is long-term ROI, not &quot;fun&quot; or &quot;functionality&quot;. This applies to both games and business software. Fun and functionality can&#x27;t really be quantified in a way that&#x27;s consistent or comparable across products.<p>Some of the most successful games aren&#x27;t really much fun for the most active players, such as MMORGs and free-to-play mobile games. They seem to succeed more through triggering addiction and a sense of competition amongst players rather than providing an enjoyable experience.