Early in my career, an inexperienced manager (me) learned the valuable lessons and fine art of delegation of duties. In the beginning, to spare few words, I "sucked" at delegation. When I delegated something, I always had an idea in my head of how the finished product should look. When the work came back, rarely did it look as I had envisioned. I then changed my employee's work to conform with my idea(s).
My first mistake was not communicating my vision clearly. Then, I exacerbated that mistake by reworking the hard work of a valued employee. In many cases, I wasn't just "tweaking" the end product; I was remanufacturing it as if I had done it myself. Now, two of us did the work of one and neither of us were happy. In the process, some ingenious ideas were overlooked to the detriment of everyone.
Soon, I learned how counterproductive my methods of delegation had been. The reason to delegate in the first place was to spread the workload, not to double it. Micromanagement might be the best way to demotivate an employee. If your goal is to keep your employees down, micromanage them. If your goal is better productivity and happy employees, then learn to accept good enough as good enough and move on to the next project. If you must "tweak", do so sparingly.
Steve Jobs said, "It doesn't make sense to hire smart people and tell them what to do; we hire smart people so they can tell us what to do."