How did humans evolve so successfully while other animals lacked in the process of evolving?

Almost all animals alive today are successfully evolved, apart from a few things like the tuatara which has been largely left behind by evolution because it lives on a sheltered, isolated island. Some species do get shafted because conditions change suddenly and more rapidly than they can adapt to, usually because some human introduced cats into their environment - but most were well-adapted to the conditions which existed *before* that sudden change. Nor are we the most successfully evolved animal, since we tend to destroy our own environment and then starve. The best adapted mammal is either the brown rat or the house mouse, and the best-adapted animal overall will be whatever the most common species of nematode is.