It would be very hard not to get a strong negative impression of Tom Sawyer and Huckleberry Finn after reading Chapter 2 of Mark Twain's The Adventures of Huckleberry Finn.
Mark Twain cleverly uses the exposition of the story to openly expose the mischievous nature of these two boys, particularly, Tom as a leader and Huck as a follower.
In this chapter we encounter the boys planning a lot mischief in the form of a cruel practical joke towards Jim in which he would end up tied to a tree, and then forming a "band of robbers".
The impression that one gets is that Tom and Huck are the basic dyad of a very dynamic duo that basically "runs" the entire town and attracts other kids to do bad things. Tom is the mastermind who is both educated and somewhat privileged, as he comes from a quite respectable household that has done nothing good for him. Huck is also a kid that comes from a good but dysfunctional home, always fearing his father like a child would fear a monster. Jim is the scapegoat of both Tom and Huck, who play pranks on him because, after all, he is their "property" and they are entitled to do so.
However, the sense of maliciousness in the boys is so big that one wonders if a modern child reading this story would not find it disturbing. An example is the plan that Tom creates for the gang to maintain loyalty:
So Tom got out a sheet of paper that he had wrote the oath on, and read it. It swore every boy to stick to the band, and never tell any of the secrets; and if anybody done anything to any boy in the band, whichever boy was ordered to kill that person and his family must do it, and he mustn't eat and he mustn't sleep till he had killed them and hacked a cross in their breasts, which was the sign of the band. And nobody that didn't belong to the band could use that mark, and if he did he must be sued; and if he done it again he must be killed. And if anybody that belonged to the band told the secrets, he must have his throat cut, and then have his carcass burnt up and the ashes scattered all around, and his name blotted off of the list with blood and never mentioned again by the gang, but have a curse put on it and be forgot forever.
To the modern reader, these are very strong words to come from a pre-pubescent child, especially when this particular child is none other than Tom Sawyer, the master child-manipulator.
In all, the boys are the typical adventurers who like to assert their boyhood by playing pranks, imagining adventures, and giving themselves an identity of outlaws and meanies.