A lot of people are busy arguing who to blame, I just think it&#x27;s interesting that sometimes you need to support non-standard software. Actually, I think it&#x27;s interesting that highly successful programs are not the ones who go &quot;not my fault, you should just implement the spec better&quot;.<p>Raymond Chen talked[1] about the importance of supporting that ran on Win95 but broke on WinXP, even if they weren&#x27;t complying to Microsoft specs.<p>I also remember reading that web browsers had to go to great length to render completely non-compliant web pages.<p>In your experience, when should you decide to support &quot;non-complying&quot; behavior?<p>[1]: Unfortunately I cannot find the original article by Chen but I could find extensive mentions of it in [this article by Joel Spolsky](<a href="http:&#x2F;&#x2F;www.joelonsoftware.com&#x2F;articles&#x2F;APIWar.html" rel="nofollow">http:&#x2F;&#x2F;www.joelonsoftware.com&#x2F;articles&#x2F;APIWar.html</a>)