The concept of a "sympathetic character" is one of the many elements of popular or bourgeois literature that Samuel Beckett was attacking in Waiting for Godot. In a sense, a "sympathetic character" can be a stereotype, leading a viewer to a simplistic emotional response to a play (think of a film with obvious "good guys" and "bad guys") rather than making the viewer think. Thus even Lucky changes from victim to oppressor to subvert the possibility of sympathy. An important way of thinking about Vladimir and Estragon is when Vladimir says:
"Our Saviour. Two thieves. One is supposed to have been saved and the other (he searches for the contrary of saved) damned."
Vladimir and Estragon, like the two thieves, can either be viewed as saved or damned, but which they will be cannot be determined except by the reaction to them of Godot who never arrives.