Engineers are often beaten into a "no, because" mentality by managers who only hear the "yes" or the "no" and not the universe of constraints under which that conclusion is given. Being a "yes, if" person can be a recipe for disaster unless you really trust the people you're working with to be able to understand the challenges that need to first be overcome. Let's be real: the overwhelming majority of business people are not as brilliant as Walt Disney.

In my opinion, a better approach for an engineer in typical real world conditions is to be a problem solver while controlling the message. "Yes, if" gives up control of the message. Instead of saying "yes" rephrase and reformulate the idea into your own words while adding the necessary constraints. It's a small difference, but it allows you to take full ownership and control of what you're signing up for.