1) I tried co-founders, but found that they didn't work as hard as me. Most people like to be lazy, so finding someone with the same work-ethic is difficult
2) I want to make decisions quickly and having a co-founder could slow that down for me
3) Employ people quickly who can help you. You don't need to give up part of your business to get good people. What motivates people is not just money - its often pride in a good job, good working conditions etc. I always run a very flexible in terms of time that people work. They work when they want and always get the job done
4) Don't be afraid to fire people. There are "givers" and "takers". I always fire takers as soon as I recognize them.
"And so, my fellow Americans: ask not what your country can do for you — ask what you can do for your country."