Five lessons learned from the summer's box office hits and misses

As Hollywood's summer movie season winds down over Labor Day weekend, the box office results can be summed up in one word every studio executive wants to hear: up. But a season that saw more than its share of surprise hits also had a handful of surprise misses - and proved the only reliable trend is the bankability of superhero blockbusters.

Below, a look at five lessons learned from the biggest flubs and triumphs of the season.

SEQUELS PAY

Though Disney's "Avengers: Infinity War" opened a week before the official start of the summer box office season, the movie's mammoth success established early on that this would be a summer of sequels.

By the first weekend in May, the film (released