Here's another one: failing to think the whole picture through.
The Me-163 Komet (which, yes, I can't stop making fun of) had these 4 basic premises. And no, I'm not talking about dissolving the pilot, or the other well known stuff.
1. It had an extreme climb speed, but abysmal range. It depended on being directed from ground exactly WHERE to climb, because even relatively small errors meant the B-17s were out of your reach now.
2. Because of that abysmal range, it had to be moved very often between airfields in the path of anticipated enemy raids.
3. They were directed by women auxiliaries. Which would be perfectly fine, except...
4. According to Third Reich doctrine, women who weren't in direct combat roles couldn't be ordered to move around. (You know, since they were supposed to go home in the evening and make and raise babies.)
You can probably see where this is going. Every 2-3 weeks you'd be on a different airfield, where the women directing you were just now learning that the Komet even existed, and were desperately racing to learn on the job how to calculate the ideal intercept point for them. They made mistakes. Then you'd get moved somewhere else, where a completely different set of newbies would struggle to learn from scratch how to do that.
Oh, they were perfectly capable to learn. Just by the time they got half-way decent at it, it would become irrelevant, and another set of newbies would start hurrying to learn it from scratch.