There was four decades of great sectional conflict between the North and South. There were deep economic, social, and political differences. There were many reasons why the South wanted to succeed but the main reason had to do with the Norths view on slavery.
There were a few reasons other then the slavery issue, that the South disagreed on and that persuaded them to succeed from the Union The South wanted to reserve all undefined powers to the individual states. The North also wanted internal improvements sponsored by the federal government. This was more roads, railroads, and canals. The South, on the other hand, did not want these projects to be done at all. Also the North wanted to develop a tariff. With a high tariff, it protected the Northern manufacturer. It was bad for the South because a high tariff would not let the south trade its cotton for foreign goods. The North also wanted a good banking and currency system and federal subsidies for shipping and internal improvements. The South felt these were discriminatory and that they favored Northern commercial interests.
The main reason for the Souths secession was the Slavery issue. When new territories became available in the West the South wanted to expand and use slavery in the newly acquired territories. The North opposed to this and wanted to stop the extension of slavery into new territories. Congress passed the Missouri Compromise of 1820. Southern extremists opposed