In literature conflict is defined as a struggle between two opposing forces; these forces can be external or internal. External conflicts exist between a character and nature, a character and society, or between a character and other characters; while internal conflicts are those within a character. Here is an external conflict:
In Stave One of A Christmas Carol, Dickens, Ebenezer Scrooge is greeted cordially by his nephew Fred who wishes him a Merry Christmas. However, Scrooge is angered and asks him what right he has to be merry; Fred retorts by asking his uncle what right he has to be dismal. Scrooge responds with his "Humbug!" but the nephew still persists in his cheer. In great disagreement with this ebullience of his nephew, Scrooge declares,
"...every idiot who goes about with 'Merry Christmas' on his lips should be boiled with his own pudding and buried with a stake of holly through his heart! He should!"
"Uncle!" pleaded the nephew.
"Nephew!" returned the uncle sternly, "Keep Christmas in your own way, and let me keep it in mind."
"Keep it" returned Scrooge's nephew, "But you don't keep it."
In another example of conflict, one that is internal, in Stave I (page 5 of enotes's e-text), Scrooge sees Marley's face in the doorknocker, but goes upstairs to his room muterring "Humbug!" Yet, with the face of Marley in his mind, he double-locks himself in his room. Then, he hears a noise and a rattling of chains. Marley's ghost appears to him:
No, nor did he believe it now. Though he looked the phantom through and through and saw it standing before him; though he felt the chilling influence of its death-cold eyes; and marked the very texture of the folded kerchief bound about its head and chin, which wrapper he had not observed before; he was still incredulous and fought against his senses.
After Marley's Ghost shows Scrooge his chains and explains that he has come to warn him, he tells Scrooge that he will be visited by three spirits, beginning the next night. Marley's ghost departs without disturbing the locked window, and Scrooge falls asleep in exhaustion. When he awakens the next day, Scrooge
thought, and thought, and thought, and thought it over and over, and could make nothing of it. The more he thought, the more perplexed he was; and the more he endeavored not to think, the more he thought. (Stave II, p. 1 on enotes e-text)
Certainly, Scrooge is engaged in quite an internal conflict as he does not know what to make of the visit from Marley's Ghost. He persists in his efforts to disbelieve, yet he knows what he has witnessed.