How do criminals and people get so caught up in crime they can not get out of it ?

I’ve been watching a lot of movies and it amazes me the kind of lives some people live. I’m wondering how people get so caught up in crime, they get deeper and deeper into it. And start to do things like kill, steal, betray their own families, and risk their life for money, or gold, or whatever. When you are in this position is it because you have gone so deep there is no way out? Do some people do crime (like rob for example) only because it’s fast money? Or they don’t think they can work “legit” jobs? Or is it because they have no fear of getting caught, arrested, killed, etc?