"If you don't know you know, you think you don't know.
If you don't know you don't know, you think you know."
For a artist,
"What you think you can, maybe you can't.
What you think you can't, maybe you can"
and,
"What you think you can is the limit of your ability."
A little explanation:
Muscle memory, or automatism is essential in playing music.
But it should be obtained at level of controlling instrument. Your
muscle should be trained enough to create automatically the sound your
ear wants to hear, but your ear shouldn't be trained to want the sound
your muscle automatically create.
During a practice session, you should fully concentrate so that the
your
ear demands muscle to produce better music, more beautiful tone
sonority,
sharper edge of sound, more exact timing, more accurate articulation,
more dynamics, or, in short, 'more expression' you can think of that
given moment, so that the muscle will memorize the best result it ever
produced and will remain flexible to react to additional ideas of
variations.
Whole purpose of practicing is enable you what you can't yet.
If you practice much without enough concentration, while your ear is
lazy,
muscle will memorize lower level of movement (bad habit) too, and it
will
delay your later development.
It's better idea to practice without watching TV, fully concentrated to
the sound you create, and reserve TV to the time when your head or body
is too tired and need relaxation.
It's good idea, however to practice with music from radio or TV, BTW.
It's instant source of ear training and playing purely by ear.
Whatever song is going on, you pick the melody, guessing next chord,
reharmonize it as you can, seeking the way of playing suitable to that
music and participate as if you're additional arranger to that music.
Trying to absorb musical idea of the song, (if any), and if it's poor,
it's your - arranger's challenge to embellish it.
Just a humble opinion of one of ever developing learner of music...
BTW, I never practice while watching TV, because I don't have it. :)
I learned much more thing in my life since I sold it.
muchan