With the capitalism, the job's kind has changed.
Men work in places that are not their places and where they are not familiar. Men produce objects that they don't know what they are.
When you see a factory's production line, it reminds you a Charles Chaplin film. A man participates in a little part of the whole and he doesn't see the totality. This is the alienation. The alienation of the job. The alienation of the job's result.
But, what's the job's result? It's the product, i.e., goods. A product is a strange object because it has a value. We can exchange it, exchange it by any other.
This value seems to be natural, but it isn't. This product with value is known as fetichism. But its value is produced by whom? It's produced by the labor of the man: the abstract labor... And everything can (and need to) be sold. Even our labor!!!