How seriously do you take Polonius' precepts (1.3.58-80)? Consider especially the last one (1.3.78-80).

Act One contains Polonius’ most famous speech in the play, and one of the most quoted speeches of Shakespeare, the advice speech to Laertes that ends, “to thine own self be true” (I.iii.55 ff.). One can weigh the various maxims here offered on the basis of their individual merits. However, it is a common mistake of new readers of Shakespeare to take this speech simply at face value – to think, in effect, that Shakespeare, not Polonius, is giving this advice. This is never the case in Shakespeare – he never simply speaks “through” a character – and most certainly not the case here. Notice, for instance, that Polonius’ speech begins by telling Laertes to rush off to catch his boat, and then detains him from doing just that. Notice also, that Polonius begins by declaring that he will offer Laertes a “few precepts,” then goes on to ramble for thirty lines. Polonius, in short, never misses an occasion for a speech, and follows his own advice creatively if at all. His meddlesome, didactic character leads to his undoing, as we shall see.