Be careful what you wish for
Do you sometimes wish that you could just make a decision and have the troops fall in line without any dissension? After all, if everyone agreed with your ideas, you'd have a lot less stress and you'd get things done a lot faster. Actually, there's a good chance that your wish will come true sooner than you think. Over time, your immediate team's thinking will naturally gravitate toward your point of view -- for better or for worse. It's no picnic for them when you're obviously stressed out. So they'll eventually lose interest in asking those penetrating questions, without even realizing it. And that's exactly why you need to search out some different opinions sooner rather than later.
Feel the pain before it's too late
Good ideas sometimes lead to good solutions, but bad ideas almost always produce disastrous results. And when you come up with a stinker, you'll probably be the last one to realize it. Unfortunately, the longer you cling to that bad idea, the more damage you'll do to your business. That's why it's better to let your idea take a beating early on. Find out whether your idea has merit, before you invest a lot of time and money pursuing it.
It's not about feeding your ego
Where's the first place that you go when you want an opinion? Be honest. You probably go to someone who is likely to agree with you. In fact, many executives start by trying to build momentum for their ideas by selectively amassing opinions that support them. They will then leverage support from their buddies to control the discussion in a larger group meeting. It doesn't take a genius to figure out what happens next. Surprise! The idea will be unanimously endorsed, and the executive will once again prove that he's brilliant. Of course, everyone who thought (in private) that the idea was a dog will do what they can to undermine his plans. And all forward progress will come to a grinding halt. Everyone will then ceremoniously lament over the failure of such a wonderful idea.
Look for help in all the right places
Admit it. You've seen this story unfold many times before. So what can you do to avoid the same routine? Make sure that you look outside your normal operations for independent advice. That's the only place that you're likely to find unbiased opinions. In fact, try to find smart people who are NOT familiar with your mission and who are hearing your idea for the first time. You'll never be able to figure out if your idea is sound when everyone is drinking the same Kool-Aid. Make sure that your idea can at least float on its own before you set out to swim with the sharks.

