Why does this bother me so much, does this happen to anyone?

whenever i hear All I Want For Christmas Is You by Mariah Carey, i start to get teary eyed. i have a boyfriend that i love very much..but for some reason this song just makes me sad, usually at the beginning then towards the middle and end i'm not sad anymore.. i don't think it has anything to deal with my ex or anything like that...i don't get it. are there any songs that bother you and you don't know why?