2. The Chitauri Shut Down When You Blow Up Their Home Base
The Chitauri are supposedly an incredibly advanced alien civilisation they've got spaceships, levitating leviathans and they look pretty damn adept, too. They sport advanced weaponry, can clamber up buildings and get around on air-chariots. All in all, they're a pretty terrifying foe to go up against, especially en masse. Yet the one place where they chose not to strengthen was in ridding themselves of shutdown switches, apparently. It's a horrible oversight here we have the scariest army the Earth has ever seen, armoured up, clambering buildings and bloody extra-terrestrial, and they all drop dead when Stark blows up their HQ. This is the equivalent of saying blowing up Edgehill will cause the SAS to suddenly stop working, or that bombing MI6 would suddenly cause James Bond to stop having sex with things. It's insane logic and plot convenience at its finest I get the phrase 'chop off the head and the body will die,' but really, that only works for bodies, not working armies. They'd be disorganised, sure, but they'd still be dangerous. Honestly, I think it would've been cooler if the stranded Chitauri became the most conspicuous insurgency ever, but looking at it, that probably wouldn't have been 'neat' enough.