Please have trust in your designers. Sometimes we have to take extra time to prove things to you, like creating and alternate floor plan to prove that a sectional sofa is the wrong choice or searching for an image with the exact paint color they are proposing in order for you to approve. Many of us are billable hourly, so this can cost you more money in the long run as well as strain the relationship.
If you feel that you have to micromanage your designer or that you couldn't trust them to make decisions without you, they are not the designer for you and you should fire them. Designers are not furniture dealers, let them use their full range of talents so that you can enjoy the experience of having a designer work for you.
Your designer is not a threat to your good taste but proof of it. Despite what HGTV will lead you to believe, nonprofessionals cannot perform as well as professionals. There is no shame in living in a designed home just as there is no shame in wearing designer clothes instead of sewing your own. Your designer has more than an 'eye', they have the contacts and technical knowledge it takes to make certain that goods are manufactured and installed properly.
Please have trust in your employees. Many of us spent a great deal of money and energy getting a formal design education so that we could someday work with someone like you. We know that we are not as experienced as you, but we do have resources that you don't - mainly, the vast network of contacts that we made in design school who are now employed by your peers and competitors. We discuss many aspects of the industry together, such as which vendors we use, mistakes we have seen and made and what type of projects we are working on. As a result, we know more about the industry than you might expect.
Allow us to communicate with clients since we often have the most up to date status information and can answer their questions more readily. It does not make you look bad, in fact it reinforces the fact that you are successful and busy and do not have the time for paperwork. We can run interference for you when clients are high maintenance, showering them in attention and also telling little white lies about what you have been working on. We can allow you to be in "two places at once" by visiting workrooms or job sites. And let us do our own installations, you don't need to watch movers spread out carpets or place furniture according to the plans. You can show up at the last minute with flowers, move an accessory or two and take all the credit.
If you cannot trust your employees to install, supervise and specify than you should fire them and find better ones. Also understand that it you will not involve them in these aspects of projects they will feel unappreciated and dissatisfied and either leave your firm or not perform as well. We want to earn our pay, we are not interns.