Hal set about obtaining honor through a charade of nonchalance. He made himself appear to be lazy, so when he ascended the throne, the people would be even more appreciative of him when he did a good deed.
Also, the political-courtly relationships are very peaceful on the surface but contains many back-stabbing underneath. Within the thieves, the back-stabbing is on the surface, without any pretends. The heir to the throne who grew into the world of hypocrisy, the honesty between the thieves (in which you know your enemy's identity), provides a certain security and confidence. .
The first sign for Hal's change is when Henry summons him. After a long lecture about the suffering he underwent to seize the throne, King Henry ends up weeping that he loves his son even though Hal seems unfit for the throne. Than Prince Hal replies, saying, "I shall hereafter, my thrice-gracious lord, / be more myself".
The relationship between a father and his son is an important theme in Shakespeare's Henry IV, Part One, as it relates to the two main characters of the play, Prince Hal and Hotspur. These two characters, considered as youths and future rulers to the reader, are exposed to father figures whose actions will influence their actions in later years. Both characters have two such father figures; Henry IV and Falstaff for Prince Hal, and the Earl of Northumberland and the Earl of Worcester for Hotspur. Both father figures for Hal and Hotspur have obvious good and bad connotations in their influence on the character. For example, Falstaff, in his drinking and reveling, is clearly a poor influence for a future ruler such as Prince Hal, and Worcester, who shares Hotspur's temper, encourages Hotspur to make rash decisions. The entire plot of the play is based on which father figure these characters choose to follow: had they chosen the other, the outcome would have been wholly different.
Prince Henry's soliloquy at the end of Act One, Scene Two reveals that his character is not as low as it would seem to be.