Well roundedness, in the case of small business owners they need to be able to do all aspects of business reasonably well. What I find most often with businesses that don't make it, there is an aspect of the business that they do not do well and they can't get over that component of the business. For some businesses they may be unable to manage money, in other cases they can't sell, some companies can't collect after a job is completed, for others it may be accounting and record keeping. The list can go on and on because there are so many components to running a business. The important thing is to identify what you don't do well and have a professional in that area handle that part. You may pay a premium price for this service, but if do what you do best and let the pro handle where your week I think this is the key to building a successful company.