When someone decides to cross illegally into the United States, they have to make what is essentially a cost benefit analysis. The benefit is obvious,they can make more money here than in their home country. The costs are much greater.
The first problem is getting across the border. That means paying a smuggler. It can cost a thousand dollars or more. Then if they are coming from Mexico, they have to evade Border Patrol agents while crossing the hot Sonoran Desert. Many die in the attempt. In addition they face robbery, rape and death at the hands of the Coyote who is leading them.
If they make it safely to their destination, they face hard work at low pay, often getting cheated by their unscrupulous employers. As a stranger in a strange land they have few social contacts, usually in their own ethnic community. Living arrangements are usually poor. Farm laborers often live in hovels not fit for a dog. Those in cities fair no better, cramming four or five people in a one or two bedroom apartment.
Being here illegally they have to be on guard, looking for immigration agents who will send them back home if they are caught. Restricted to an ethnic ghetto, being illegal, they have few opportunities for enjoyment. Aliens live in constant fear of getting deported, robbed or worse. It's a miserable existence.
For most humans, family and loved ones are important, but those here are far from home. Loneliness takes its toll. Depression, alcoholism or substance abuse is common. Sometime suicide seems the only way out.
Some adapt, bring their family here, and live a relative normal life, underground. Many are caught, sent home and face the dangers of returning. All and all, it's a life not fit for man nor beast.