"If you are living for the future, you aren't all here"
Alan Watts puts it most elegantly although both the past and the future are rendered useless without being in the present. Haste makes waste so their is no point in being in a rush to get no where(now-here). Focusing on the past inhibiting my future only takes away from today; and worrying about tomorrow robs from what can be done today.
The power of now makes every moment eternal and rushing futile.