If you feel you have to micro-manage, then....
1) You may have done a lousy job at selection and mis-hired.
2) You may be piss-poor at clearly identifying the objectives for employees so they can get the task done right.
3) You may be headed for the cardiac ward sooner than you think.
4) You may end up with greater employee turnover than you can handle or expect.
5) You are inadvertently undermining any employee interest in being innovative or gaining organizational knowledge (why learn to tie your shoelaces if mom always does it?)
6) You may find yourself lost in the details and losing perspective about the macro aspects to be attended to.
Allison makes a good point that attention to detail CAN be a means for providing guidance and shaping skill. If it is broached as preparing a fledgling employee for flying on their own, and desists soon after, then it's mentorship not micro-management. If it happens in spite of employee confidence and skill, and persists, its micro-management.
As I keep repeating ad nauseum, the secret to effective management is to surround yourself with competent cooperative people, clearly identify the higher-order and concrete objectives and underlying rationale, provide the human, informational, and tangible resources for people to get the job done, and then get the hell out of the way.