It is important to identify what the mood is in Act I scene 5, which is when Hamlet confronts the Ghost and finds out the truth of what happened to his father. The mood in this scene is one of horror as Hamlet struggles to comprehend what has happened and also tries to work out whether the Ghost is speaking truth of not. There is a deliberate contrast between this scene therefore and Act II scene 1, in which Polonius instructs Reynaldo, a hired spy, about the best way he can check up on Laertes. Polonius can be presented as an over-punctilious, bumbling fool, and this scene certainly could be used to support this image of him. Note the advice he gives Reynaldo, who clearly knows his job better than his employer:
Take you, as 'twere, some distant knowledge of him,
As thus: "I know his father and his friends,
And in part him"--do you mark this, Reynaldo?
Polonius presumably has to check that Reynaldo is listening at this point because Reynaldo, who probably is incredulous that he is being told how to do his job, is trying his best to not show his contempt in his facial expressions. This scene, therefore, compared to the horror and serious tone of the previous one, is one of comedy and humour. There are of course, links between both, as they both involve fathers who are trying in some ways to manipulate and keep an eye on their sons.