"A visual bug seen by all your customers might do more damage to your program's reputation than a rarely occurring crashing bug."
This is recommended by Microsoft in its "Windows Vista User Experience Guidelines: Rule 12". Internally, if they followed the same guideline for developing Windows Vista, we can easily tell what will be its quality. After all these years of delays, once its put to use in large scale, if we see the same kind of crashes and hangs that we have come to expect in any of their products, it would be no surprise. Come on guys, prioritize functionality and reliability first! Everyone wants a good looking app, but also the one that works for them.