Why did upper class people fear Jackson becoming president?

Jackson was the son of poor immigrants from Ireland, had little formal education and lived on the frontier in Western Tennessee. Upper class people were uncertain of what he might do if he became president and his Western friends and supporters took on positions of power in the government. I think people always tend to fear change even if they are not sure that it will be harmful. In fact there is an expression: "A known evil is better than than an unknown good,".