God is relational because God is God. God is not relational because he creates human beings. You were not created for relationship because God needed a relationship with someone. He has always been in relationship. He is–by nature of his very God-ness–relational because he is Triune–Father, Son, and Holy Spirit.
This means that God is intensely personal. Therefore the Trinity should not be reduced to merely doctrinal matters. God is not a math problem or simply a logical, linear arrangement of theologizing.
In the Triune God the relational aspect of existence is given infinite weight and meaning.
Eugene Peterson writes,
So we don’t understand Trinity by working with numbers, puzzling over how one equals three or three equals one. Trinity has nothing to do with arithmetic. Trinity is the church’s way of learning to think and respond relationally to God as he reveals himself to us as Father, Son, and Holy Spirit. God is triply personal, emphatically personal, unrelentingly personal. Growing up in the practice of resurrection must also be unrelentingly and emphatically personal. [Practice Resurrection, 198.]
However, this works the other way round also. Those who prize the practical and the relational nature of Christianity should not get frustrated with those who discuss and debate the complexities of Trinitarian theology. Without the Trinity the personal and relational nature of Christianity is reduced to a finite size. In the Triune God the relational aspect of existence is given infinite weight and meaning.
Getting personal matters because theology matters. Relationships matter because God matters.
The affirmation of the Trinity on the statement of faith at your church that you probably have never even looked at means something. It’s important. It’s worth defending. It’s worth celebrating. It’s a statement about the nature of reality, and, not only theological reality, but everyday–communicating with your wife and kids and neighbor–reality. Therefore value relationship and getting personal not for its own sake, but for God’s sake and unto his Triune glory.