[k__]

Learning to play an instrument feels like magic.

You fail the whole day.

Don't have the feeling anything sticks.

Then, the next day it works right from the start.

No new insights, nothing, it just works.

[XCSme]

I am coaching table-tennis, and sometimes I tell people that we only actually "learn" while we sleep. So, without sleeping, the brain doesn't have time to "save" the new information for future use.

Not sure if it's factually correct, but it seems about right, sleeping seems to be the magic sauce, and the time when all memories are written from RAM to disk.

[Qem]

I never played any instrument, but I had the exact same experience getting through difficult stages in videogames.

[k__]

Yes, me too.

It seems to be a thing with practicing motion sequences.

[sobjornstad]

I've noticed the same thing with rote memory tasks like lines of poetry, so I think it might be a more general thing involving the memory consolidation properties of sleep, maybe particularly focused on fluency/speed rather than mere ability to recall.