The author of the OP is a Jewish atheist, so indeed probably hasn't attended a lot of Christian church services. I think "you may need to shop around" is too s

The author of the OP is a Jewish atheist, so indeed probably hasn't attended a lot of Christian church services. I think "you may need to shop around" is too strong. A churchgoer may care about other things besides whether the music at their church is exciting to them, and it's not obvious that they should prioritize excitement over (say) theological agreement, or strength of community, or what if anything the church does outside its services. The white robes arguably do come from the biblical account. Revelation 7:9: "After this ... behold, a great multitude which no man could number ... clothed in white robes". This is describing specifically "they who have come out of the great tribulation", so it may not be meant to apply to everyone there, but there are a whole lot of other white robes in Revelation. The lyres, too, or possibly harps. Revelation 15:2ff: "And I saw ... those who had conquered the beast and its image ... standing beside the sea of glass with harps of God in their hands". Again, not obviously everyone, but harps none the less. No walking on clouds there, though. And in any case it's not clear that taking Revelation as a straightforward account of what to expect in some future existence really matches much with its actual intention. Those white robes and "harps of God" and all the rest are all there as symbols of purity and worship and the like, and arguably the author of Revelation was much more interested in commenting on contemporary persecution of Christians in the Roman Empire than in actually predicting the future. (Note: I'm not a Christian, though I was one for many years. Feel free to discount any of the above as a result, if that seems appropriate to you.)