Nobody is out there to oblige you. All employers try and exploit the perceived vulnerabilities and in a situation of demand and supply you are not wrong to hold out for the maximum possible. your service and the capabilities you bring to the job is in fact a commodity and you have to sell it for the maximum; of course, the maximum is a sum total of money and other intangibles. But, if it becomes evident that the company is trying to exploit you, you owe them nothing at all.