I enjoy the give-and-take that comes with trying to guide a Customer toward what I perceive to be their best interests. Doing that with multiple Customers in parallel means that I have victories and defeats. That's heartening and engaging to me. I would find it very demoralizing to continue to engage that way with a single party over and over again. I found it that way back in the "bad old days" when I was an employee, and I'm certain I'd find it that way again.

When I talk about being self-employed I like to say that I traded having a single "boss" for multiple "bosses"-- one or more from each Customer. One thing that I've really enjoyed, to that end, is being able to cut my losses with a given Customer if the situation becomes untenable. That option wasn't so easy when I was an employee. An employer, in most of the US at least, has the freedom to be fickle at any time for arbitrary reasons. Being self-employed, to my mind, helps to level that playing field.

Being an employee amounts to running a business with a single Customer. If that Customer leaves you've suddenly got a business with no Customers. New Customer acquisition costs are very high (especially in the employer-provided health insurance world of US employment) and Customer loyalty can be very low. It's a precarious situation to me, not one I'd ever want to be in again, and not one I'd counsel someone to put themselves into.