You've finally made it to the campground. But before you can run off to the lake or go for a hike, the first order of the day is to park and level your RV so that your refrigerator will operate properly and you don't find yourself in bed at night with your feet higher than your head.
Never assume your site will be flat or level. That would make parking an RV too easy. Due to the nature of camping, chances are higher that your site will be rutted, gouged and somewhat uneven.