Being self-employed can be very rewarding. Allowing you to pick your own hours (to an extent), choosing to run your own business the way you want to and even choosing which clients you work with can make running a business worthwhile and out weight many of the negative points, but you do need to have a high level of discipline to be able to do it successfully.
Time management is one of the most important factors when it comes to owning a business as you will need to make sure that you have time dedicated to working on client work as well as time for updating your accounts and touting for business. If not managed correctly you can very quickly end up in a mess which can cost you dearly in time and money. You may also be responsible for managing the time of any staff that you have should you decide to set up a limited company or outsource work to another individual or company.