If you are offered a wage, you must take it. You can try to bargain, but there are many more in just as desperate a situation. You can try another business, but they are each just as greedy and self-interested -- they each try to squeeze every last bit out of their "human resources." Everywhere, the Capitalist is the same in their interests and desires.
What happens if you reject the wage? Well, without an agreement, you can't work and be paid, but your boss does not receive labor. However, there are probably many others at the same business, and they would be able to compensate. In no time at all, another laborer can be found to replace you. Not because they are better at the job, but because there is widespread poverty. And there has always been starvation and hunger everywhere in Capitalism, because it is essential for exploiting laborers.
Within a week, you are replaced, but without pay, you are unable to pay for food, rent, and necessities. Your boss is just as well off now as he was when you worked for him. It is a matter of bargaining power: you can only go to other capitalists who are just as exploitive, and the boss can find other workers just as needy. Without pay, you are close to starvation. But without your labor, the Capitalist can live off of his plenty for a long time.
As a worker, you are in a hopeless position; you have no right to determine the hours you work, what your job consists of, your pay, or how your business is organized. Whether you are happy or not at your job depends on all of these things. But as a laborer, without any bargaining power, you can't change them. You're in a position that is only somewhat better than a serf: the wage-slave.
Of course the management will offer incentives for doing better work. That keeps us divided. We see each other as enemies to increasing our pay. Instead of cooperating with each other, we compete. But, if only we would unionize, we wouldn't have to worry about another five cents more per hour. We could cut our work day in half and double our pay. We struggle against each other, for just a little bit, when we could work together, and create plenty for all.
And how much better off is the worker who was rewarded a pay raise? Do you not realize that they may just as arbitrarily decrease your pay? Do you not realize that you are just as likely to be fired and discharged when the next economic panic comes? You have accepted your boss's method of improving your standard of living. Now you will be its victim when there is a recession or "business is restructuring."
The only way to genuinely protect your job and standard of living is to unionize. As a single worker, you are helpless, and your resistance to the system is weak. But as a working class, you are powerful, and withdrawing your labor all together, would bring Capitalism crashing to the ground. Unionize and Strike!