"orchestral tissue without music" — of one very long, gradual crescendo. There are no contrasts, and practically no invention except the plan and the manner of execution. - Ravel on his own work, which is an iconic classical piece.Also, Bolero is adored and loved so much, but then there's this
Perseveration, an Alzheimer's symptom, is the obsession of repeating wordsThis is from an article that purports that Bolero was an indication of dementia. That's why the repetition.
or actions, and could have been the mastermind behind Ravel's infamous masterpiece.
It is known that beginning in 1927 or 1928 — the year he wrote Boléro — Ravel began to experience perplexing health problems.

Interestingly, as I read in the kusc blog,
'In an interview published in London's Evening Standard, February 24, 1932, Ravel said, "I love going over factories and seeing vast machinery at work. It is awe-inspiring and great. It was a factory which inspired my Boléro. I would like it always to be played with a vast factory in the background."'Does this explain the repetition? The hammering of repetitive sounds, gaining crescendo as the day progresses. The dawn of the new sound -- metal -- and the onset of repetitive music that is popular today? Was Bolero an announcement of the new age of music?
Back to you, listeners, is the music repetitive (it certainly is) despite its melody and more importantly can you enjoy it up to its length or do you tend to lose interest.
‘There are no contrasts, and there is practically no invention except in the plan and the manner of the execution…I have done exactly what I have set out to do, and it is for listeners to take it or leave it.’ - RavelAre the subtleties -- change in instruments, loudness, style -- good enough to fuel your interest or do they not work for you. Importantly, the subtleties could be predictable for some. They are predictable for me. At the ninth minute mark I wondered if it was written as incidental music for a play.
Bolero was originally composed as a ballet, I learned.
It would sound much sweeter for a ballet, when the eyes would trace the movement of the ballerina and the music with its repetitiveness and predictability wouldn't distract.
‘Don’t you think this theme has a certain insistent quality? I’m going to try and repeat it a number of times without any development, gradually increasing the orchestra as best I can.’ - RavelAlmost every instrument gets a chance to play the theme. It starts sparsely with the soft flute, going on towards a crescendo played with a full orchestra. I am certain you will enjoy the melody. Do you think it's long and is it enjoyable throughout? Here are some interesting shorter versions.
An animated seven minute version:
A four minute version with a dancing Violinist:
A pop six minute version:
References
NPR
The Orchestral Bassoon
KUSC-Dennis Bartel