Why do immigrants come here illegally, if it's as easy to just come here legally?

I would like to understand why it is that so many people come here illegally(risk their lives and the lives of their childrens) if as alot of people are saying that the process is as simple as filling out paperwork.?

Well for starters, it takes a long time for the paper work to process. Also there's a couple of tests you have to take. It's not really EASY per-say, but it's so much easier than risking your life and leeching off the United States and the benefits it offers.

I have absolutely no sympathy for illegal immigrants and I think they should all go back where they came from and if they want to come here should do it properly. I honestly feel it's absolute B.S. what they d. That's all just my personal opinion though.

All I want to do is marry my U.S. girlfriend, and trust me here, it's not an easy task at all. You have to negotiate so many ups and downs, and all the Red tape it's SO frustrating!
All I want is to be with her, I don't want anything from the US at all, not even the benefits. If I can work there to support us, then I will. The wages that are paid there aren't all that great anyway compared to here, but I'll do what I can for the both of us.
I wouldn't mind, but really I must be one of the few people who doesn't actually WANT to live in the USA, and If I could marry her over here, then I would!! (but unfortunately that's not an option for us; divorce, young children, US law etc. etc.)
I certainly don't condone or in anyway support illegal immigration, far from it, but I'm starting to see why people take their chances.