In short, if you're going to spend the money to work with a creative, hire the best one you can get–someone you trust. Listen to them. Consider their advice and if you are not 100% sure that your way is better, follow their guidance. That's what you're paying them for. As I once told a client who wanted to know why he should trust my opinion over his own, "Because, on this topic, my opinion is better than yours. In fact, that's why I get paid and it's the only reason I'm here."
"Not what I had in mind" is bad feedback when you're working with a creative professional (designer, writer, photographer, etc.). In fact, getting something that is "not what you had in mind" is the point. What they bring back to you shouldn't be your idea on paper. It should be something better than anything you could've come up with on your own. If it doesn't surprise you and make you a little nervous, THAT is a good reason to ask for another try. They are the expert. They have knowledge, talent and experience that makes them better at this than you are. If they don't, either find someone who does or do it yourself (not a good idea, BTW). Another REALLY bad idea is lying to seem open-minded. You'd be surprised how often people withhold their thoughts and ideas either out of laziness ("I don't have time to think this through now") or wanting to seem like the cool open-minded client. Be honest. Give them your thoughts and ideas up front. All of them. You're saving everyone a lot of pain and frustration in the long run. And if you already have your mind made up on something, tell them before you hire them. "I like my idea but I'm open to something better" is a crappy way to approach a project. You're limiting the possibilities up front by comparing them to some vague concept in your head that you're already attached to. Personally, I won't take that project and neither will most good creatives. There's a reason "I'll know it when I see it" is a joke. Don't be that client.