Now, granted, I realize that the formula for Most Depressing Day isn't particularly scientific , but I find it quite suspicious that it's chosen the same day at least two years in a row, now.
But for those who're looking for a little Tuesday depression, here are some suggestions on how to prove the scientists right:
to one or more of the following:
- The Clientele, "K"
- Dios, "Just Another Girl"
- Dusty Springfield, "Breakfast in Bed"
- ABBA, "The Winner Takes It All"
- Jane Birkin, "Fuir le Bonheur"
- The Go-Betweens, "I'm Allright"
- The Beach Boys, "You Still Believe In Me"
- The The, "Love is Stronger Than Death"
- The Afghan Whigs, "When We Two Parted"
- Willie Nelson, "Blue Eyes Crying in the Rain"
The Godfather: Part II. Or, maybe, watch it more than once! It gets more uplifting the second & third times round—I promise. 
Happy Sad Day!
 Best song ever.
 This is the frighteningly new-agey, feel-bad formula, btw:
The model is:
[W + (D-d)] x TQ
M x NA
The equation is broken down into seven variables: (W) weather, (D) debt, (d) monthly salary, (T) time since Christmas, (Q) time since failed quit attempt, (M) low motivational levels and (NA) the need to take action.
Of course, it leaves quite a few questions unanswered:
- What about the southern hemisphere, where the temperature in January can be above 100 degrees Fahrenheit?
- What about people who celebrate another holiday (or none at all) instead of Christmas?
- What if I have no motivation whatsoever, which would cause M to be (presumably) 0, which would cause a division by 0 condition, leading to an infinite amount of... something?
- & most importantly: What is the final unit of measurement? Days? Weeks? Minutes? Number of depressed people?
 Not really. But it does tend to numb you after a while, which can be helpful.