Not an uncommon theme for Beckett works, all the characters come in pairs of two. Estragon and Vladimir are always together on stage, and are completely codependent on eachother. Estragon threatens to leave on more than one occasion, but neither of the men ever move. Another of the pair is Pozzo and Lucky, whom are never seen apart. Pozzo and Lucky's relationship is strictly master to servant respectively, the two are also never seen apart on stage. The only character who isn't part of a pair is The Boy, though he speaks of his brother whom is not on stage. So, the only character who doesn't have a partner is Godot. Godot is meant to be alone, putting him on separate plane than the other characters.
One of the common interpretations of the play is as if it was a Religious allegory. Much can be read into Beckett’s inclusion of the story of the two thieves (Luke 23:39-43) and the ensuing discussion of repentance and it is easy to see the solitary tree as representative of the cross or indeed the tree of life. And, Godot is often thought as a God figure. The conclusion is easy to make, since the similarities between the name Godot and God. “Beckett said to Peter Woodthorpe that he regretted calling the absent character ‘Godot’, because of all the theories involving God to which this had given rise. “I also told [Ralph] Richardson that if by Godot I had meant God I would [have] said God, and not Godot. This seemed to disappoint him greatly.” Even the boy can be related to the Christian faith. For example, the boy claims to be a goatherd, while his brother is a shepherd. In the Bible, goats represent the damned while sheep represent those who have been saved.
It is also speculated that Vladimir, Estragon and Godot represent the id, the ego and superego respectively. “Bernard Dukore develops a triadic theory in Didi, Gogo and the absent Godot, based on Freud’s Trinitarian description of the psyche in The Ego and the Id (1923) and the usage of onomastic techniques. Dukore defines the characters by what they lack: the rational Go-go embodies the incomplete ego, the missing pleasure principle: (e)go-(e)go. Di-di (id-id) – who is more instinctual and irrational – is seen as the backward id or subversion of the rational principle. Godot fulfils the function of the superego or moral standards. Pozzo and Lucky are just re-iterations of the main protagonists. Dukore finally sees Beckett’s play as a metaphor for the futility of man’s existence when salvation is expected from an external entity, and the self is denied introspection.”
As stated in the character section, many of the characters are represented by an article of clothing. Estragon disheveled appearance sows not only his lack of effort in presenting himself with dignity to the human race, while Vladimir's cleaner appearance shows just the opposite. As previously stated, Estragon often had trouble with his shoes and at one point throws them on the side of the road in disgust. The fact that he is so focused on his shows portrays him being lower in society. While Vladimir is often seen fussing with his hat, portraying him as being a part of higher society. The same represenation is shown with Pozzo.