Rationality vs Human Nature.

I will agree with Hobbes by the fact that a monarchy is the best kind of rule only if he considers that monarchy to be in what most of us would call a perfect world. His ideal common wealth and government grossly underestimate human greed and desires to the point that its obvious there is so such perfect world where his system would work. Human desires will undoubtedly overcome the very rationality that Hobbes bases his theory on. It is suggested that the monarch will always do what is best for the people because it is the people who willingly keep him in power. This is rational to the point that it will never happen. His goal is only to keep the people happy in so far as they do not revolt. Even though Hobbes will object, it has nothing to do with keeping peace for the peoples sake. The monarchs desire is not to keep the people happy for their sake - he does it for his own sake. This will create animosity of the subjects.
Not only is there a problem with the monarch's desires, there is also a problem with desires of the subjects (aside from peace atm). I believe it is human nature to seek power and do whatever is rational to get that power. Hobbes might agree but not to the point where we would both say that this desire to seek power will overcome the rationality between the monarch/subject relationship. Even though the subjects are perfectly capable of understanding the rationality of obeying law, they do it only because of consequences rather than because its rational. If this is true, Hobbes account is wrong. Thoughts? If I were a subject, the only reason I would obey the law is to prevent any bad consequences. Otherwise, I would follow my human desire to rise above.