You know the kind of person who forgets silly daily tasks like brushing his teeth? Parson Adams probably would forget his wig if it wasn't glued to his head. Sure, he's a totally brilliant scholar who can quote Aeschylus for days, but he mistakes his beloved sermons for "none other than three shirts, a pair of shoes, and some other necessaries" (2.2.1). He's not the most observant about worldly matters.
Maybe he's a little forgetful because his mind is occupied with more philosophical matters. Adams teaches Joseph that it's okay to think about big-picture concepts, like charity and education. Not everyone responds so well to this kind of intellectual forgetfulness. One gentleman traveler Adams meets "at first sight conceived a very distasteful opinion of the parson" (2.7.7). Luckily, like most things, Adams doesn't even notice.
Accuse Adams of forgetfulness, but never make the mistake of accusing him of cowardice. Adams is always ready to rush to the attack with his fists or his crabstick, as he does on many occasions. When Adams hears a woman screaming in the distance, he immediately "offered to snatch the gun out of his companion's hand" (2.9.2). And that's after a big burly hunter just ran away from the danger.
That's the thing about Adams. He always strikes people as hypocritical when he's preaching, but that's because they don't see him in action. Adams believes wholeheartedly in those dratted sermons, to the point of stubbornly insisting on placing himself in danger. He's always looking for an opportunity to practice what he preaches, but that usually comes in the form of punching someone in the mouth.
But hey, in this novel, whoever's getting punched in the mouth usually deserves it.
For someone who's a parson, Adams sure gets in a lot of fistfights. We're thinking he doesn't really have the opportunity to indulge his "punchy" side when he's back in the Booby parish. Not only can this dude "bear a drubbing as well as any boxing champion in the universe," but that trusty crabstick also helps even the score.
Why all the violence? If we had to guess, we'd say that Adams's passions run high. He feels strongly about all that he says and preaches (see above), and he's willing to back up his words in any way he knows how. When a grumpy innkeeper gives him grief about the people and concepts he works so hard to defend, he realizes that the only way to get through is a good one-two. We don't advocate this approach, obviously, but it certainly seems to work for this guy.
For all his violent tendencies, Adams is a pretty devout guy. While encountering some dangerous sheep-stealers, Adams "fell on his knees, and committed himself to the care of Providence" (3.2.6). Although he has his crabstick as a backup, Adams takes his duty as a parson pretty seriously.
Specifically, he's concerned about making sure his parson duties translate to the real world. That's why he preaches at every opportunity to everyone who will listen—and to some folks who don't. Even though being pious should be a given for parsons, Fielding shows us that Adams is an anomaly among a bunch of hypocrites. Adams's old-fashioned tendencies to preach and quote his sources are light-years away from what's going on in the rest of corrupt society.