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:
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.