Can you give an example or two where it is not sane to expect the same results over and over?

It is a common idea that we can just "go back" to the past and if we just, say, rekajiggered union laws back to what they were at the height of unions, or rekajiggered immigration laws back to what they were in 1950, or reset the healthcare system back to what worked in whatever time, that we could recover the same results of that time. It won't work, because the world has changed too much. (Which is not to say that they are good or bad ideas, or that they wouldn't have some kind of effect of some sort. But they certainly would not simply recreate the past.)

Politically, it is difficult to convince people of the oncoming disaster of guaranteed-benefit entitlement programs, because they've worked up to this point so why can't we just keep doing the same thing and expecting the same result? But if you've got changing ratios of number of people on the programs vs. the number of people supporting them, you can't expect the same results to obtain.

You can't expect to just keep using the same antibiotics over and over indefinitely and getting the same results.

As we creep closer and closer to the possibility of being able to recreate extinct species and re-introduce them back into their original ecosystems, there's an interesting debate occurring about whether that's even a good idea. Once a species is removed from a niche, is it possible the ecosystem rearranges itself such that reintroduction would be a net negative? (This gets into its own tricky issues about how one can actually define "net positive result to an ecosystem" which so far we've been able to sort of skirt around with various heuristics, but with this sort of power becomes an unavoidable issue.)

In your personal life, there's really quite a bit that over the span of decades you can't expect to keep doing the same thing and getting the same result. Getting drunk and staying out all night doesn't have the same result at 22 as it does at 52. Exercise programs have to change. Careers have to change. Children change everything. Your own political opinions will have to change (is it really sane for a 55-year-old to have the same opinions about everything that they did at 15? what a weird world that would have to be). Your financial practices will probably have to change.

Change is the only constant in life.

Generally when you do the same thing over and over, you expect to improve over time; we call that "practice."

I don't follow. If you get better each time, then you aren't "doing it the same" each time when you practice. Each practice is naturally unique and fine tuned to the level you are at.

If you are saying that every time I practice, I get a little better, then this is in accord with repeating consistent results.

Flipping a coin?

Edit:

(except of course you generalize the result to "the coin falls down").

Or "you get heads or tails" or "it spins through the air before bouncing around a bit".

I think most of the examples one could give can be mitigated by rewording your expectations. Which, incidentally, is the reason for the quote in the first place.

Well, by that logic, everything could be reduced to "stuff might happen".

Right, and if you reduce a quote to a tautology, you miss the point.

It's like complaining that a metaphor isn't literal.

Not entirely. I don't really have a quarrel with the quotes message (I wouldn't really care, TBH), but with how it's used. And sadly, it usually is used to dismiss someone's efforts by misinterpreting the other person's motives (or "expectations") - which coincides with exactly this pattern.

So basically, whenever I read the phrase so far (luckily, I never had to hear it in a personal discussion yet), someone uses it to belittle someone else without taking his/her perspective into account. Or any changes to the world as a whole for that matter.

I can see that, thanks for sticking with me :)