Paul models that in Romans 1:11-12, our word for today from the Word of God. He says to the believers in Rome, "I long to see you so that I may impart to you some spiritual gift to make you strong - that is, that you and I may be mutually encouraged by each other's faith." Paul seems to understand this tributary thing. His purpose in wanting to be with these people is so he can give them some help, some encouragement, something that will make them stronger. He also looks forward to how they are going to feed his stream, too, enlarging his spiritual life.
Now, this is an exciting way to view the relationships in your life and the people in your life. You are with those people both to give and to receive. I wonder if your co-workers, your family members, your friends, and the folks at church feel richer because of the good things you keep depositing in their life. You're supposed to be one of God's designated tributaries to help them become the mighty river that He's designed them to be. You wouldn't be there with them if He hadn't decided they need someone like you, and that you need someone like them.