Answer:
Being able to interpret the letters on this screen proves that you have this quality.
Known to accessorize with feathers, trumpets, and harps.
Three little letters, a paradox to some. The worse that it is, the better it becomes.
Runs smoother than any rhyme, loves to fall but cannot climb!
Whoever makes it, tells it not. Whoever takes it, knows it not. Whoever knows it, wants it not. What is it?
I start with T end with T and within me is T.