In this vein, Jim Collins' classic business book "Good to Great" is a must read. His central thesis -- backed by years of research -- is that THE key to great success (and not just good success) is an unwavering focus on what your company can do better than any other company in the world. In other words, the key to great success -- once you have identified that "thing" -- is to only resource that "thing" and just say "no" to everything else.
This is especially true for smaller companies, I would argue, given their particularly limited resources. All of us are barraged with loads of opportunities -- many of which seem truly "great." But, as Collins points out, the truly successful companies understand that they must relentlessly focus only on those limited opps that are directly in their defined sweet spot. So, no matter how great other opps may seem, no resources should be expended pursuing them.
The bottom line is that management teams must learn that saying "no, no, no" is as important -- perhaps even more so -- than saying "yes, yes, yes."