A Neutral Evil character only cares about himself. His only morals, ethics or purposes are self-interest. There is only honor, when you win. There is only morals, when you feel good about it, the world be damned.
You can care and love for others of any alignment, but if shit gets wild or tricky, you most likely will not risk yourself for anyone, but you.
90% of the time you will behave pretty much like Neutral would, and maybe sometimes even attain Neutral Good, but it is because of your self interest of self preservation, nothing more. You are not good, and you could never be, how could you? You would never care that much for anyone else, the way you care about you.
Neutral Evil is probably the wrost alignment of the game, because it is trully awful. It tops Chaotic Evil, because Chaotic Evil follow a shitty pattern that is easily recognized, as well as Lawful Evil, who still bears some sense of the lawful aspect of the alignment, while you, a Neutral Evil, don't have any sense of anything besides "I am the most important thing in the world and universe, and that is that". Selfish, callous, and most often than not abandoning your group (could be anyone, really) to save your life and limb. You are the guy who loses 1HP and ask the healer to heal you first, no questiosn asked, despite the fact that your best friend is bleeding on the floor, dying.