Get In Line
The problem with the cartoon is that it's actually a gross oversimplification -- the immigration process is far more byzantine than the nice straight arrows in the diagram. For example, the cartoon doesn't get into the consequences of criminal convictions, which can bar you from getting status depending on the nature of the crime, the severity of the punishment, and the mood of the judge.
The law on criminal bars to immigration does, however, give some (depressing) insight into the U.S.'s priorities. It's actually easier to get around a domestic violence conviction than a drug paraphernalia conviction. The U.S. would rather have a citizen who beat his wife than one that had a bong.