Jesus tells the disciples that they are not servants. They are friends. Both of these words do not quite give us the full impact of what Jesus was saying. Servant is the same word used for slaves throughout the Bible. "Friends" is the same word used for beloved throughout the Bible, too.
Jesus says that the disciples are not slaves. Rather, they are beloved.
We are also part of Jesus' beloved, since he claimed us as his own by his death and resurrection. We don't serve him like servants. We serve as his beloved. This difference in relationship is makes a big difference in how we approach daily life.
Servants serve because they are compelled to, because they fear punishment from their master. When you only respond because of fear, you do what you must to avoid punishment but no more.
When you serve as a beloved member of the family, Jesus' business is your business. You do it because you care about what the family does. You freely desire to do your best for Jesus and the rest of his family.
Servants also don't get to make decisions about how and where to serve. They only obey the master, who gives them orders.
Beloved family members know the Father's business, so they have freedom to choose. Since they don't have to fear punishment from the Father, they can use their best judgment when approaching new problems and practices.