Six sharps are fun ... Seven even more so. I can recommend the C# major fugue from the WTC 1
Yes, I know, I know, I already forced myself through that crazy 7 sharp prelude, the fugue MUST follow. However, anyhow I feel myself distancing a bit from Bach on piano, instead probably remain on Chopin for piano but Bach on organ. Have to make hard decisions regarding practising time. There are still voice lessons every week and music theory because of the church music education I have right now, so time, time, time ...
This little machine is changing the way I practice.
Same happens to me. One gets less tolerant to flaws I think. Necessary is only that the fun and aim for musical expression does not degrade on the endless journey towards perfecting a piece. That would be the worst thing what can happen.