Weapons developers keep forgetting that you have to develop weapons for use against a foreign enemy, not other Americans:
For example, during the 1980s, the CIA got a largely intact Russian anti-missile flare system from a Russian warplane that had crashed in Afghanistan. This was given to American aircraft technology experts for examination. The flare system was actually put back into service and tested. Then it was discovered that the Russian flares were of uneven quality and this turned out to be a big deal. When tested against the latest American heat seeking air-to-air missile, which was designed to avoid these flares and go for the aircraft, the Russian flares fooled the American “flare detector”. That was because the “flare detector” had been tested using American flares which were manufactured to more uniform standards than their Russian counterparts. If a flare did not match what the flare detector had been programmed to recognize as a flare, the missile went for the Russian flare, thinking it was an aircraft.
Poor manufacturing standards by the enemy again embarrassed the Americans during the 1991 Gulf War. The U.S. Army sent Patriot anti-aircraft missile systems that had been modified to knock down Russian designed SCUD ballistic missiles, to defend Saudi Arabia. Iraq had hundreds of SCUDS and fired some of them into Saudi Arabia. The Patriot anti-missile capability worked, sort of. The Patriot was designed to detect and destroy an incoming SCUD. But the Iraqis had modified their SUCDs (by lengthening the missile to carry more fuel and have a longer range). This was done in a crude fashion, and when the SCUD came down it often came apart so that the intact warhead was often accompanied by other parts of the missile (the engine and lengthened fuel tanks). This, in effect, provided decoys as the Patriot radar could not tell the difference between the SCUD warhead and other missile parts. Sometimes the Patriot missile shot down an empty fuel tank instead of the warhead. The Patriot anti-missile system developers had not paid attention to this problem and lives were lost as a result.