You want all the money they can give you. They want your labour for free if they can get it. The deal you end up making is somewhere between those two extremes. The business needs someone to make money, but often doesn’t necessarily care who. They can pick the applicant that suits them best, providing the most value for money. They have something you want, and you may not have something they want, so they have all the power.

If you have experience or an education in a field with a worker shortage, you can get the opposite effect. See, for instance, the IT sector a few years ago, which had companies like Google and Facebook hiring people to do literally nothing all day, just so their competition doesn’t get their hands on the valuable workers. In those negotiations, there are plenty of companies that want to hire these people, so they have a lot of power in the negotiations. They’re doing the company a favour by “settling” for their offer.

Businesses don’t make a lot of profit from feelings. Even friendly people need to take economics into account, and that’s what most job offers are about. The same is true in reverse; you can work for the nicest, most caring boss you could ever imagine, but if you can’t make rent, something will need to change. Your negotiating power depends on what you have to offer, and what the other side has to offer in return. If you have nothing special to offer, you’re the one who’s going to have to settle. For jobs that don’t require any special education (or don’t ask for any experience), they are doing you a favour by hiring you, because you’re probably scratching the bottom of the barrel for jobs, and you can’t get anything better. If you had any better options, you wouldn’t be applying to such shitty companies.

The reason they’re treating you like you’re scamming them is a) most people they hire probably are putting in minimum effort, because there’s no way anyone is going to work themselves to death over minimum wage and b) they’re deadly afraid of you gaining the upper hand. If you become too good at your job, and the business starts relying on you sticking around, you may demand a raise or leave for a better job, leaving the business in the vulnerable position without much power. The longer they can keep you doing jobs that don’t require experience or leave you in a position where you’re replaceable, the less likely it becomes that you’ll be a threat to their bottom line, which is often tied to bonuses and other benefits for management. This is especially risky for business that run on quite thin margins, where the money all flows to the top, like grocery stores. This is where career advice like “become irreplaceable” comes from; a lot of career advice actually comes down to “get yourself more bargaining power”, packaged in non-offensive terms like “add valuable contributions”.

If you’re not applying to jobs with minimum requirements/wage and you’re still getting contempt, the interviewer is probably just a dick. You get those sometimes. In those cases, the interview is as much about you learning if you want to work for a company as it is about the company vetting you to work for them. If you have other options, it’s best to politely decline and find someone to work for who does respect you. There are bosses out there that do value the people working for them, but the good bosses don’t stick around dead-end jobs for too long.

Related: this bargaining power is exactly why unions are important. You, as one single employee, can probably hardly work yourself into a position where you can negotiate a better deal, but if all the employees in your sector decide to lay down their work all at once, businesses suddenly start to panic. They can make exceptions and special deals with the two or three workers that can negotiate themselves upwards, but when it comes to bargaining power, nothing beats dozens of workers coming together, leaving entire chains haemorrhaging bonus money as their business closes because nobody mans the machines/tills/registers.