But it is not the goal of worship, it is not an end in itself. Our worship should not communicate something false about what it feels like to be a Christian. Again the Psalms are a helpful guide in this - they do not romanticize the Christian life. This does not mean that worship is always somber and heavy, but it should always be light and familiar either. I am arguing for a more full demonstration of the character of God reflected in our worship.
People sing differently standing than they do sitting.
I am not going to tell you what to do when, but I do want you to think about it and include body posture in your thinking about worship. We should pray corporate prayers, read scripture, and confess our faith using creeds, together.