Even other characters in the movie don't find the action scenes believable when they hear about them second hand.
The Hero has just invoked Rule of Cool seven times in a single ten minute action sequence. His daring escape has involved acrobatics on an upside down airplane, turning a nearby tank of flammable gas into an improvised jet pack, and single-handedly defeating an army of henchmen using nothing but plastic utensils... ...and when someone tries to explain this to anyone who happened to be off screen at the time, it comes out sounding just as ridiculous as it is. Strangely enough, characters in works that seem to tax our suspension of disbelief to no end sometimes seem to operate on the same notion of "plausible" that we do, and when something that happens offscreen is explained to them, they don't believe it any more than if your friend had told you Superman had stopped a trainwreck on the six'o'clock news last night. Related to Cassandra Truth
Mooney: Sergeant, you don't believe me. I swear! Flying, with a big red cape! And bright red boots as well! Quick as a wink he was gone! Flew up in the air again, he did. Like a big blue bird.
Sergeant Dolan: [snip] Like a big blue bird.
Mooney: You don't believe me.
Sergeant Dolan: With bright red boots. [snip] Why don't you take the night off and go back to Murphy's bar and continue what you started. I'll be off myself in a few minutes and meet you there myself.
[They go outside and see Superman flying away]
Sergeant: Mooney, the first bottle's on me. I'll get my hat.