In Christian Discourses, Etc., the Danish philosopher/theologian Soren Kierkegaard has a chapter entitled "The Anxieties of Self-Torment." It's a comment on the Gospel of Matthew. He leads off the chapter with the verse from Matthew: Be not therefore anxious for the morrow-- after all such things do the heathen seek.
The kicker is this: in essence, Kierkegaard says you're greedy if you worry beyond the day. (Okay, okay, covetous is a shade different.) He declares that one who trusts in the care of a Higher Power [no, no, you're absolutely correct; he says "the Christian"] does not have this anxiety.
Every day shall have its worry, that is to say, take care to be free from the next day's worry, accept tranquilly and gratefully the worry of today....for every day has enough of its worries. In this respect also God provides: He measures out the amount of worry which is enough for every day, so take no more than what is measured out, which is exactly enough; to be anxious for the next day is covetousness. [Walter Lowrie translation]
I'm not razoring in on how profound this affected me when I first read it, around 1979 or 1980. It struck me how radically useless it is to not live in the day, "this very day," as Kierkegaard terms it.
For me, personally [forgive the tautology], I used to go with "Eat, drink, and be merry, for tomorrow we may die!" But it was a cry of desperation and despair. Today I say the same words out of gratitude and celebration, somehow infinitely different--which I am explaining very poorly.
Speaking of today, this morning I put an "I Leap for Kierkegaard" little bumpersticker on my car. I bought it from my own website (www.laughorism.com) many weeks ago.
Then I wondered if doing so lowered the value of my 1999 Ford Contour because I'll probably never be able to scrape it off the bumper, which is the same olive color as the rest of the car.
Sheeeeeeeeeeesh! Talk about neurotic.