We see that Horatio does not simply listen to Hamlet but also takes actions and measures that he believes shall provide Hamlet with respite. He actively chooses to put his own life in danger in order to protect Hamlet and seeks out ways to get Hamlet out of trouble (Coan). On the other hand, while Horatio continues to take care of Hamlet, we observed Hamlet to progress through the plot in a manner that is nothing less than reckless. He makes decisions that isolate him from the very people he loved when the plot begins and gradually develops a nature that is fundamentally hostile.
Hamlet continues to plough through obstacle after obstacle throughout the course of the plot but very rarely does he move from one part of the plot to the other without first consulting and seeking advice from his close friend Horatio. Hence, we can surmise that had Shakespeare not developed the supporting character of Horatio, the plot may have progressed in a manner very different from the one in which we observe him today (Morgan). Hamlet’s actions may have been based on a far more extensive degree of irrationality than they currently are and maybe Claudius would have been able to cause damage to Hamlet much sooner in the plot. For instance, when Hamlet comes across Yorick’s skull, it is Horatio to whom he refers his sorrow.