Johnny is the title character in Esther Forbes's novel Johnny Tremain, and at the beginning of the story he is not a particularly nice person. Some things happen in his life to change that, but when we first meet him it is difficult to like Johnny Tremain.
When the story begins, Johnny is the star apprentice at a silversmith shop; unfortunately, he is also arrogant and unkind. He continually points out the faults and flaws of the other, less talented apprentices; though he is more talented at working silver than they are, he is blind to his own prideful behavior. As a kind of retaliation and to teach Johnny a lesson, two of these boys give Johnny a faulty piece of equipment, causing an accident with hot silver which essentially welds the fingers of Johnny's hand together. This accident only serves to make him more surly and unkind.
With only one working hand, Johnny can no longer be an apprentice as a silversmith, so he has to find another place to work. He has a bad attitude because he assumes no place he would like to work will hire him, and he is correct. The kinds of places which might hire him, such as a butcher shop, are not good enough to meet Johnny's standards (and his high opinion of himself). His bad attitude is compounded when Isannah (one of the daughters of the silversmith for whom he apprenticed) exclaims. "Don't touch me! Don't touch me with that dreadful hand!" This makes him even more self-conscious and bitter.
Eventually he meets Rab, an apprentice at a printing shop, and Johnny's attitude slowly begins to change because of Rab's good attitude and friendship. This friendship and the loyalty of Priscilla (the silversmith's other daughter) help make Johnny a better person and certainly a better friend.
Eventually Johnny becomes an integral and trusted part of the Revolutionary War activities in Boston. Though he loses his friend, Rab, in the war, Johnny regains the use of his hand when one of the doctors performs an operation.
Though Johnny is an arrogant, thoughtless, unkind young man at the beginning of the story, he learns some humility and gains some friendships which help him change into a better and more admirable person. The two apprentices Johnny so mistreated did, unwittingly, allow Johnny to learn some very valuable lessons about himself and how to treat others.