Cast Off

I am faithful
I do not leave you
You use me every day
Sometimes you run, each footfall pains me
But when you stand I itch to run
I would stay with you forever
But you always discard me
Pass me on, cast me off
I see no tears of remorse
When you do

I am not the one who changes
It is not that I no longer fit you
It is that you no longer fit me
Yet I do not abandon you