A day job to me is essentially trading time for money. It is usually separated into two broad categories. You can either choose to work for yourself or work for someone else. Both entails advantages and disadvantages that we should take note of. However none of these decisions should curtail your financial philosophy. There are frugalists, capitalists and frugal capitalists who are financially successful on both sides of the spectrum.
Being self employed often means being an entrepreneur. Property agents, stock brokers, insurance agents, freelancers and online/offline business owners are a few examples. The advantage of working for yourself is that you are responsible to yourself, Your financial future is in your own hands(some people might think of this as a disadvantage).
Most self employed jobs are self running "businesses" which means you will have to contribute your own CPF and health insurance. Scaleable business often means difficulty in starting ......