The experience we have during during worship -- whether excitement, emotion or sobriety -- could be a reflection of a legitimate encounter with God. Or it could just as easily be a natural reaction to the music itself, which is why people who have been to both have said that attending a Grateful Dead concert is like attending a Pentecostal worship service. Is God behind the music, or does music trigger a part of our brains that makes us think of God
And since you can see a substantial development in the understanding of God just in the Tanakh, from an arguably moral but still decidedly tribal deity who kicks Gentile butt because the Gentiles are picking on his people, to a deity who transcends national boundaries and desires all the nations to live by love, there is some credence to the notion that we've been making it up as we go along. Or maybe God's been revealing himself steadily by degrees all along, and Christ is just the final and ultimate expression of that revelation. (But then even there, there've been some pretty striking developments in how we understand, interpret and incorporate Christ into our lives over the last 2,000 years.)
Occam's razor suggests the simpler, more obvious explanation is probably the true one. Unfortunately, that bastard Occam has shaving cream too, and that makes it so it's impossible to say which explanation really is simpler and more obvious, except by personal bias, and so once again we see an eponymous philosophical principle walking around with bits of Occam's toilet paper stuck to its face.