John Piper describes true worship as:
Worship must have heart and head. Worship must engage emotions and thought. Truth without emotion produces dead orthodoxy and a church full (or half-full) of artificial admirers (like people who write generic anniversary cards for a living). On the other hand, emotion without truth produces empty frenzy and cultivates shallow people who refuse the discipline of rigorous thought. But true worship comes from people who are deeply emotional and who love deep and sound doctrine. Strong affections for God rooted in truth are the bone and marrow of biblical worship.
(DESIRING GOD, Multnomah Press, 1986.)