Yes it is glass half empty and intentionally so. The point is that it takes time to reason about problems, understand more than individual perspectives and evaluate solutions to problems. I have shot myself so many times in the past by having a quick answer to a question even if I was previously convinced it was a good idea.

As for letting people know what you say yes to, all problems need the same evaluation therefore which leads to assumptions that you will say yes. Sometimes people don't ask and just assume. Another road to hell.

It's not evasive either. There's nothing to say that you're not going to sit there and work through it with them, engage with other people and come up with a solution based on pooled ideas.

Perhaps I should say I never say yes or no until the adequate amount of research has been done.