Fencing exhibits this phenomenon nicely. Fencing does not come even close to mimicking a real sword fight. One reason for this is right of way, basically the id

Fencing exhibits this phenomenon nicely. Fencing does not come even close to mimicking a real sword fight. One reason for this is right of way, basically the idea that the person who attacks first gets precedence and the onus is on their opponent to defend against the attack before attacking themselves. However what is defined as an "attack" in fencing is very different from what a layperson would assume. Really, it's defined as forward movement without a clear intention to take the blade. Which means that tactics such as advancing with ones arm held back are rewarded. A lot of people, upon hearing this, respond with something along the lines of "fencing is stupid! We should make our own sword fighting system that encourages real fighting!". HEMA is a nice example of this. Putting aside the questionable logic of a martial art based around swords, what inevitably happens is that as the system develops, people want to compete, to see who is the better fighter. Since they clearly can't judge fights by, well, murder, they need to come up with a rules and points system. Once this system develops, someone starts to realize "hmm, if I do x action, I can win fairly easily". Thus a meta develops. Once a meta develops, everybody starts using the meta to win and the fighting becomes less mimicking killing people with a sword and more competing in a sport. Some argue that the way to prevent this is to not have competitions or rules. But...then you have a bunch of people waving around swords with no clue as to whether it's actually effective. Side note, fencing has had a few of these major meta developments in its history too. Johan Harmenberg famously pushed epee's meta to be a lot more athletic and dynamic.