At one point Alexander and his mother where actually both banished from the kingdom. It was also a well know that Phillip tried to demean Alexander at every occasion where he had the opportunity to do so. Once, shortly before Phillip died, he had an altercation with his son at a party, the origins of which where apparently never recorded. The dispute elevated out of control, and Phillip drunkenly lunged at his son, only too fall face first onto the floor. To this Alexander remarked, "Look men, he's about to cross from Europe to Asia, and he falls crossing from couch to couch". Not quite the Brady Bunch. .
Phillips death is still a mystery to this day; much like Alexander's would be a short while after. Some claim that Alexander and Olympia plotted out his death, but there are too many hypotheses on this subject to try to come to a solid conclusion. Any way you look at it though, Alexander became king, and what a great king he was to be. He started out on the conquests his father had only thought about. This could have been just out of spite, to do himself what his father had wanted to do; or it could have been sheer delusions of grandeur, which in Alexander's case didn't end up being quite so delusional.
For the majority of his life, Alexander must have been confused as to what he was to become. From his relationship with his father, we can see perhaps he felt a need to prove his own worth to others, or it could possibly just be a sheer hatred enough that he wanted to sully his father's memory by overshadowing him so much, that he may be looked upon as inferior to his son. I do not believe that the latter is as likely in Alexander's case though, because throughout his campaigns, he was always chivalrous with his enemies, as long as they did not become overly insubordinate. Such as when he finally caught up with his great foe, Darius III, and his own people had already left him for the vultures in an attempt to spare them Alexander's wrath.