One reason that Pepys found himself so entertaining is that he did not want to miss anything out. His self-portrait, warts and all, is compelling enough to draw us in and make us live uncritically inside his skin. Moving so fast through the events of each day and the crowds of people with whom he had dealings, his energy burns off blame, making it surprisingly hard to disapprove of him. Pausing for a moment to make a few vows intended to curb his own behavior, he remarks that “my love of pleasure is such, that my very soul is angry with itself for my vanity in so doing.” He means, I think, that it is moral vanity in him to be making vows that aim above his real level, and that in his soul he thinks it might be better to remain his authentic, pleasure-loving self. More than once he says in the course of the Diary that it is right to enjoy the world while you can, because there will be times when you will not be able to. His authentic self is always so taken up with the immediate that he is quite unconcerned with glorifying his part in defending his country, and much more interested in conveying the texture and character of the world in which he is perpetually meeting new and exciting people and hearing and doing surprising things.
Claire Tomalin, Samuel Pepys: The Unequalled Self