Stackelberg Follower has a delightful post on Market failure in Christmas, written in the well-established tradition of applying formal economic modeling techniques to a thorny social problem. Here is the setup:

A model:

Denote the degree to
which advertisers push christmas by ‘Push’. This includes seasonal
music playing in malls, Santa set up in said malls well before
christmas, advertisements mentioning the number of shopping days
remaining, etc, etc, etc.

Partition the set of all consumers
into two groups. Group ‘Elf’ includes those whose utility is an
increasing function of Push. Group ‘Humbug’ includes those whose
utility is a decreasing function of Push. (Full disclosure: I fall into
the latter category.)

Claim: Elves spend more money on christmas
than do Humbugs.

The rest is here. I particularly like the postscript:

NOTE: This argument is severely hamstrung
by the lack of equation ability inherent to blogger. I’ll have to LaTeX
it formally over the holidays.