It's quite natural to be defensive in the face of criticism. After all, the critic is often someone with an agenda that's different from yours.
But advice, solicited advice from a well-meaning and insightful expert? If you confuse that with criticism, you'll leave a lot of wisdom on the table.
Here's a simple way to process advice: Try it on.
Instead of explaining to yourself and to your advisor why an idea is wrong, impossible or merely difficult, consider acting out what it would mean. Act as if, talk it through, follow the trail. Turn the advice into a new business plan, or a presentation you might give to the board. Turn the advice into three scenarios, try to make the advice even bolder…
When a friend says, "you'd look good in a hat," it's counterproductive to imagine that she just told you that you look lousy without a hat, and that you then have to explain why you never wear hats and take offense at the fact that she thinks you always look terrible.
Nope. Try on the hat. Just try on the hat.
Put on a jacket that goes with the hat. Walk around with the hat on. Take a few pictures of yourself wearing a hat.
Then, if you want to, sure, stop wearing hats.
Advice is not criticism.