You wouldn’t be hired by companies if they couldn’t exploit you. Exploitation is the difference between what you could make and what you do make, the former in the case of where you fully own the means of production that you use. Without exploitation, there simply cannot be profits.
Notably, exploitation is not just performed by business owners. Rent, interest and taxes are also paid from surplus value. This is both the rent, interest and taxes that you are paying personally out of your wages, and also the stuff that your employer is paying (since your employer pays it out of the surplus they got from you).
Another way to look at it is that exploitation falls out naturally from a theory in which the labor theory of value is true. In a capitalist economy, everything roughly sells around its value Wages are the value of workers, aka the labor/money it takes to reproduce the working class. For a society that has the ability to produce more stuff than the bare minimum, any excess production (which is called surplus) is naturally appropriated by the ruling class.
In modern capitalism, many people have the illusion that they are not exploited, because their ideas of exploitation and alienation are deeply liberal (the hegemonic ideology). They see themselves as different than the 19th century English factory man, or the child sweatshop workers that produce shoes/garments. “How can I be exploited when I can afford consumer goods and luxuries?”. “How can I produce surplus value when my labor involves typing on spreadsheets?”.
The problem with such thinking is that exploitation and alienation are not moral categories that exist for the purpose of drawing sympathy or divide the working class into productives and unproductives. That’s the liberal/fascist goal. Exploitation in Marx’s theory is that bit of energy being extracted from you to power the present order. It is a numerically quantifiable number (that stands in the range of 40-50% for most western economies).
Just as a car engine might produce net 150 horsepower but doesn’t get to decide what is done with that power, your net power output is surplus. You do not control it. Your boss who has rented you decides what happens, and his job is to whip you into working hard and working for his ends. That is exploitation.
There’s a lot of cultural stereotypes that go into the idea of “exploitation” in liberal ideology. Even many people who literally cannot afford necessities may not think of themselves as exploited, because liberal ideology teaches us that the markets give us what we deserve.
In some situations, such as factories in 19th century England or sweatshops, the brutality of wage labor can reach a level where liberals think “nobody deserves to be treated like this” and “the market is a force of goodness, but it should be regulated”.
However, the thing that makes these ideas liberal is that like all ideologies of class societies, they are blind to the reality of what makes the market system perpetuate across the generations. Instead, ideologies make us go round and round in circles talking about morality and who should get what.
The simple physical reality on the other hand is that exploitation of humans is the lifeblood of every class society that has every existed and ever will exist. Every country in which an exploitable working class cannot be reproduced over time simply dies. This applies to societies as varied as the roman empire (which had to constantly conquer slaves to fuel itself) to modern south Korea (which is on track to ageing itself out of existence).
In my experience, everybody who has learns about this dynamic about class societies becomes 10 times more class conscious.