This is the most mind-blowing thing you missed about Home Alone
Home Alone is one of the most famous Christmas movies of all time. Kevin's family leaves him at home while they go on a family trip. They forget him even though they do a couple of headcounts.
Why? Well, the stupid parents did a headcount using plane tickets. The only problem is that Kevin's dad throws his ticket away in the beginning of the movie! Check this out: