Answer:
I walked and walked and at last I got it. I didn't want it. So I stopped and looked for it. When I found it, I threw it away.
I can be short and sometimes hot. When displayed, I rarely impress.
Until I am measured I am not known, Yet how you miss me when I have flown.
Who spends the day at the window, goes to the table for meals. And hides at night?
Thirty white horses on a red hill, First they champ, Then they stamp, Then they stand still.
I am rarely touched but often held. If you are smart you'll use me well. What am I?