If you haven't seen Game of Thrones Season 8, episode 4 ("The Last of the Starks"), stop reading now.
I need to rant about the impossible—not just improbable, but impossible—success of the Iron Fleet's attack in the middle of the episode.
Now, I get that Game of Thrones is fantasy. White walkers, dragons, magic, and all that, I get it. I gladly suspend my disbelief in the fantasy elements of fantasy stories all the time. As a relevant example, when the Night King speared Viserion last season, it made sense, because the Night King was a magical being. Obviously he had a magic spear! I'm cool with that.
But dammit, get shit right when it's not a fantasy element.
Unlike the Night King, Euron Greyjoy is not a magical being, no matter what he thinks of himself. So him shooting down Rhaegal with a battery of ship-mounted, artillery-sized crossbows was total bullshit. It served the plot
Hitting a fast-moving aircraft with a deck-mounted gun is so insanely difficult that navies could not reliably do it until the 1960s. You need computer-assisted, radar-guided targeting systems and gyroscopically-stabilized guns. Or ship-to-air guided missiles, which have radar and computers built in. Even then, they miss all the time.
Before computers, anti-aircraft guns worked by saturating the sky with rapid-fire, explosive ordnance. Flying through hundreds of exploding 50mm rounds will, sometimes, bring your plane down—but not as often as one might expect. And that's true even with guns mounted on solid ground. Ship-mounted AA guns gave sailors more of a feeling than a fact of protecting their ships from aerial attack. Just ask, oh, anyone who served on a ship before the Vietnam War. Or the guys on the Arizona.
Only after the 1890s, thanks to an invention US Navy brass didn't even understand at the time and almost killed, could a ship even hit another ship reliably from any distance over 100 meters. Even in World War I ships would pound away at each other with 15-inch guns and hit one time out of 100. (Of course, one or two hits with ordnance that size could sink a ship.)
The problem is roll. Ships roll in the water, even when at anchor, even in nearly-still water. Deck-mounted guns therefore need to float freely in their mounts so that they don't change position after you have a firing solution on your target. That was the invention the US Navy didn't even want until the officer who invented it demonstrated it in a live-fire exercise.
But even if the ships sat in completely placid water, the Iron Fleet's crossbows would have huge variations in accuracy because their projectiles lack flight stability. They had small fletching and the crossbows themselves provided no rifling. (Notice the bolts in the show don't spin in flight, even though archers in ancient times knew enough to add spin to their arrows by tweaking the fletching.) I would bet half the Lannister gold that one of those things firing from a fixed position on land at a range of 1,000 meters couldn't hit a barn twice in 100 shots.
So: The idea that a ship-mounted crossbow could hit a dragon in flight at a range of well over 1,000 meters while the dragon is actively evading it is so stupid I'm annoyed that it happened even once, let alone multiple times.
And let's not even discuss the energy required to launch a ballistic projectile that large across that distance. Energy that comes from human beings winding them up. It would take minutes to reload those things using human power. So even if they scored a nearly-impossibly-lucky, fatal hit on Rhaegal, Drogon would roast them alive while they were reloading.
Bottom line: unless the Iron Fleet secretly brought a modern destroyer to the battle, they couldn't have hit Rhaegal if he were sitting on the next boat, let alone flying evasively thousands of meters away. Hell, they couldn't have hit Denarys's ships at that range, except by accident.
And no, that's not my only problem with the episode, but it's the one that annoyed me the most.