Awesome Music: The movie's theme, which plays over the beginning and end credits. For people who grew up with the movie, it's a refreshing Christmas treat outside of the typical carols associated with the season.
Crosses the Line Twice: The cat scene. The director had to beg the producers to keep it in the film and they relented when test audiences gave it the biggest laugh.
Unintentionally Sympathetic: Todd and Margo Chester. The worst they do to the Griswolds is throw some shade on Clark as he's trying in vain to decorate his house. And be yuppies. Yet they're constantly victim to Clark's destructive festivities, with frequent collateral damage to their house and occasional physical abuse.
Vindicated by History: Although the film was well-received when it was released, in the years since, its popularity has grown. It's now considered a classic Christmas film, similar to A Christmas Story and many families have made watching it an annual holiday tradition.
The Woobie: It's hard not to feel sorry for Clark at times; all he wants is to give his loved ones a perfect family Christmas like the ones he had when he was a kid, and it results in one disaster after another.
Eddie and his family, as obnoxious as they might be, mean well. The reason they showed up in Clark's driveway in their RV is because they were kicked out of their home, and they are so poor that Eddie had to tell his kids that Santa sometimes doesn't bring everyone presents.