"There is a danger in the word someday when what it means is “not this day.”...The scriptures make the danger of delay clear. It is that we may discover that we have run out of time. The God who gives us each day as a treasure will require an accounting. We will weep, and He will weep, if we have intended to repent and to serve Him in tomorrows which never came or have dreamt of yesterdays where the opportunity to act was past. This day is a precious gift of God. The thought “Someday I will” can be a thief of the opportunities of time and the blessings of eternity."
--Henry B. Eyring, "This Day", Ensign, May 2007, 89–91