I'm a realist - not a fantasist - so - yes, there are times when I feel like giving up - and if I am honest, I would say that anyone who doesn't admit to this has either a) not been in business long enough or b) is not being 100% honest!
Sorry!
My business mentor once said to me - "Businesses don't fail - people walk away from them" and that is true, but we are all human, there are days when clients are unreasonable, there are days when we feel cr*p, there are days when the cash flow is flowing the wrong way - so yes - there are days when I feel like giving up, but luckily it is those things that you have all mentioned that bring me back - they don't stop me from having that initial gut reaction "oh balls - it would be easier to get a job" but they do stop me from taking that step.
I love what I do in the main, but there are elements - as there are in a job - that I don't enjoy! But - 3 years on - I am still self employed - so I must be doing something right!
Right - that is it - the soap box is free!