"God is spirit, and those who worship Him must worship in spirit and truth." John 4:24 NASB
Worship is really an expression of faith.
At its heart, it is a reach, a stretch, wherein a person of conviction dares to seek and see God as he is. God is breath (spirit) and so he is beyond the physicality of this world and all that's in it. His essence is the essence of the soul, of personhood--self-awareness, consciousness, purposefulness. Therefore, that seeking which is worship must engage those same qualities within the seeker. That which is spirit must be worshipped in spirit.
Historically, Christian worship has fallen short in both regards. Arrangements of "furniture," postures of bodies, and recitations and intonations done virtually without thought have very little to do with worship. The contemporary fixation with worship as entertainment or a perfunctory preliminary is no better, maybe even worse. The very essence of our spiritual being must be engaged in seeking and revering God, or all we've done is gone through some empty motions.
The very essence of who we are as persons must bow before the very presence of the person of God in order to worship.
Worship must be sincere.