How does conflict affect the plot of a story?

Conflict provides a source of tension. Tension makes the story interesting, Would you rather read a story about someone getting up, brushing their teeth, eating breakfast, going to work and then coming home -- or about someone getting up to discover their rival had just moved in next door? Any conflict will move the plot along, even if it's just the conflict between the character wanting a doughnut but not wanting to gain weight.