Changes to an optimised thing make it worse

TLDR: When you make changes to a thing that has been optimised in some way, any effects of the changes you haven't planned will make it worse.

Welcome to the alien planet Sqornshellous Beta. It's dry, it's arid, and it apparently has watchmakers. You buy one. After a little while, you realise it's running a couple of milli-days slow compared to the carefully calculated local time of your ship's clock. "I should fix that" you think. You open up the back and have a look at the gears.

You know basic mechanics, so you carefully calculate the change in size to the gear pushing the second hand required for appropriate timekeeping. You buy it from the local gear shop. You fix the watch and go on your way. It seems to be running at the same rate as the ship's clock now, so, proud of your work, you go to sleep.

The next day, you notice that your watch is now behind but also running faster than the ship's clock; in the evening it is ahead, but running slower. "I should fix that", you think. You take the back off again. You spend all night, and some of the following morning, carefully measuring the turning of the different wheels and the motion of different springs. Eventually, you figure out that one particular spring is oscillating at the same frequency as the issue. You also notice that one of the disks deep in the watch isn't quite circular.

Clearly the watchmakers here aren't quite as good as their reputation. Rumours have time to evolve over galactic distances after all. You remove the spring and sandpaper the disk down into a nice circle. Should be fixed now.

As you need a mattress for your new Sqornshellian home, you take a couple of betan deci-years to pop over to Sqornshellous Zeta.

On your arrival back, it becomes apparent really quite quickly that your timekeeping hasn't fared great during the voyage. This is too much even for you to handle, so you take it to the local watch repair store.

Later that evening, you've learnt that your improved gear means you now obey the sidereal year instead of the solar year; it is also made of a different alloy, which expands and contracts differently with the heat of the day than the original. The spring you removed was the system intended to handle that expansion and contraction, and the nicely circular disk means the watch completely ignores the elliptical orbit of the planet. You have a look in the back of your replacement watch.

"Hmm, that cog seems to be spinning really fast, I should probably fix that..."

When we talk about optimisation, it is common to talk about hill climbing. It's great to be at the top of the mountain, but once you're there, literally any step will take you downhill.

If you're a half step next to the top of the mountain, most steps will take you downhill.

More broadly, so long as the mountain curves downwards, any given step away from the top is going to take you further from the peak than a step towards it is going to bring you closer.

If you're doing this in a space with a lot of dimensions, this "maybe big loss, maybe small win" becomes "definitely medium loss".

I think that there are a wide range of things this principle applies to which are of interest to this community – governance systems, human biology, and anything covered under "world optimisation". I expect people to debate me on which of these are or are not covered, and I look forward to your challenges.

Be careful when fiddling with things which have been carefully optimised. You might break them.