Seeing is believing. Sometimes the path to resolution, and evolution, of an idea means sharing your bad ideas. Yours and the clients. Sharing the good and bad, and soliciting responses, will tune your understanding of what is important to someone. And oftentimes taking risk on a bad idea will to a good idea.
Don't want to risk looking stupid in front of your client by showing them something incomplete or half-baked? That's makes sense but, remember, you control how you present your ideas. There's a big difference between showing a client some unresolved ideas and showing a client those same ideas but prefacing them with, "I didn't spend much time on these but I wanted to try something different to see where it might lead."
I'm not saying you should present all bad ideas. If you're making a final presentation to stakeholders and they expect to see something resolved you probably want to leave the bad ideas out of the presentation. Use your judgement.
At some point a client will ask you to do something that you think is a bad idea and, despite your genius, the best thing to do is to show them what they ask for. Worst case scenario: you discover that you’re not the genius you thought you were. Best case: the client sees first-hand that their idea doesn’t work and they trust you more. In either case you’ll learn a little more about the project by embracing the request and trying it out.
This doesn’t need to be a source of stress. If you’re working with a new client budget for iteration. It will improve the quality of your work and make your clients happier.