There are certainly addicts or other similar categories of people who will actively make poor choices, but there's also the matter of people who are acting on limited information and a the misbelief that what they're are doing is their best choice possible. People are not oracles and cannot get it right every time even if they have a good average. There are plenty of examples of where you can get two groups of people who will accuse each other of acting against their own interests. In some cases, it's possible that both groups could be wrong. I think you would agree that engaging in criminal behavior is against a person's best interests, but numerous studies have shown that even criminals on average tend to use rational approaches when engaging in criminal acts.
Nature tends to select against traits that are less successful even if it's a long and slow process. In another million years, humans might be a lot better at solving whatever problems filtered them up to that point. Of course the universe likes to invent new perils and humans will be filtered by those as well. Consciousness could start as some kind of adaptable random number generator, but give it enough time and filter effects and the numbers aren't so random anymore and conform to the set of numbers that favors survival. We as humans can already build these for specific, limited problem domains. I suspect in time we'll be able to make one that's general purpose and has feedback mechanisms to adjust itself at a higher level. If it can simulate its own life and death well and fast enough, it can evolve in a much shorter time than it took humans.
Research into chimpanzees is fascinating as they represent something that's possibly on its way to developing human levels of consciousness. Some researchers even hypothesize that humans developed it to be better at the same Game of Thrones activities that chimpanzees engage in. We just got there sooner than they did, but eventually their number will come up if they stick around long enough.