Is harder to get into the united states verses other countrys?

I know stupid questions right, but i was reading a article about child smugguling from the Mexico to the US, and i started thinking I wonder if its harder to get into the US then it is to get into other country's. When I got my pport all i had to do was go to the post office and apply for one and about a month later i was able to travel the world. But is the process that easy for lets say London or Africa or even Iraq. I went to Canada and London, all we had to do was answer some questions asked by customs and we were in.