Films that are either misleading in trailers or online.
For example:
Don't tell mom the babysitters dead. The trailer had me thinking it was about kids having fun when the babysitter dies. It's actually about a girl making it in the world of business.
Soylent green. The net bangs on about the ending. No one seems to mention the best part, the furniture!
Matilda. We were read the book at school. Apparently it's about a girl who reads books.., for five minutes, then she gets super powers.
There are more films, I'll try to think of what they were.
I guess a lot of films have different beginnings, but they shouldn't be sold on that.
The boy in the cupboard, Harry Potter. Serving up a great time with Sarah Connor, The Terminator. Spend time in a house full of people, Home Alone.
I guess they weigh up how best to capture the market. Parents may be more willing to buy a book for their kids about a girl who reads. Or teens will flock to a film all about shooting dishes and such. But no one wants to be served up slop by Sarah Connor.