There are several different reasons that someone may not look forward to christmas.
Alot of people don't look forward to christmas because it is supposed to be a family time... some people who have recently lost a loved one just see the absence of their presence and can only be sad because they are used to that person being there...
When my father died my mother was absolutely terrified of her first christmas with out him... it still brings up bad memories for her now after 9 years...
Another reason for people not wanting it to be christmas is that all the hype takes away the actual point of it all... it is really supposed to be a time when one can relax and enjoy the company of others but now its more like running around everywhere looking for the perfect gift... to be honest I get tired around of christmas because of this, I even get a little tired just thinking of it... In the end it is such a busy season
There is also the fact that some people being spiritually inclined, myself included, feel that the whole reason for the celebrations in the first place is being drained out by the media and the government combined... it's as if they have forgotten that it is in essence a religious ceremony, just because it is popular in the unreligious it doesn't really take away the idea behind it...
Well anyway I am sure there are more than this but I can't think at the moment