Not a movie but nobody mentioned Justified?! The opening scene of the first episode. The scene with Wynn Duffie where Raylan pulls a bullet from his gun, throws it at Wynn and says, "Next one's coming faster." The scene with the line, "A lot can go wrong with the draw." The scene where Raylan and Winona each pull and shoot the gangsters. Art's gunfight with an unseen shooter. Geez, there were so many good ones in that whole series.
For a movie, how about the final gunfight in the Shootist? Or the final shootout in Big Jake. Or the final shootout in The Cowboys?
While real life is completely serious, Seal Team 6 taking Bin Laden. Several of Carlos Hathcock's missions, like taking the general by crawling basically into his camp and crawling out, the stalk between him and The Cobra. Scary, very scary and hopefully something none of us ever have to be in.
Back to a humorous note, Carol in The Walking Dead shooting the big propane tank at Terminus and igniting it with fireworks or Daryl's using the grenade launcher on the first group of Saviors that he encountered.