George's death. We see him getting hit by the ambulance before the mall scene, but it turns out to be just a vision. As soon as we snap back from the vision, we expect Nick to suddenly turn and tackle him out of the way of the ambulance. Instead, just as Nick realizes it George gets whacked, and he essentially ignores him to go act on his new premonition.
The fifth one had several scenes played for laughs. One had Isaac in a spa asking if the Asian woman came with subtitles. Suddenly, subtitles appear.
Also in Sam's vision, when Isaac, on the phone, comes out of the bathroom to see what's going on, only to see that the bus is tipping over slowly into the water, maybe gives the most realistic, yet funny reaction in the whole film (Maybe even the whole series) with a Precision F-Strike, screaming "WHAT THE FUCK?!" in the most high pitched tone as he drops his cell.
Another example comes after Sam gets everyone off the bus after the vision, and Isaac, witnessing the bridge starting to collapse, lets out a hilarious "HOLY SHIT!" in the exact same tone as the above example.
Another one. While Molly, Olivia and Sam where at the office discussing Candice's death, Olivia says "Guess we all should have seen that coming," which is quickly followed by Sam and Molly staring at her. She then goes "What? When you see all the crazy shit gymnasts do, I'm surprised it doesn't happen more often!"
A Black Comedy example. During the opening scene when the bridge collapses, one of the girls falls into the water... And survives. Cue a car flying backwards of the bridge and landing on top of her while she floats around. If you listen closely, it almost sounds like she says "Oh fuck" seconds before it hits her.
Candice's death in the opening premonition. When she falls, you might be surprised, thinking that the movie is going to avert Soft Water. You will then most likely burst into hysterics when she gets impaled on a sailboat.