[cauch]

The problem is that YAGNI is __literally__ predicting the future: you ain't gonna need it.

How do they know that, if it is not a prediction?

In the examples I have observed, your 3 points were made impossible because early on people said YAGNI. You can always "create them later", the same way you can always "restart from scratch". Creating abstraction for a code that was designed without being compatible with these abstraction has a huge cost. And, as I've said, it is not rare that it's the users who pay the most of the cost, which mean the devs don't even know it is a problem.

As I've said, nothing is all white or all black. The problem with YAGNI is the developers think it's all white: they can decide "you ain't gonna need it" when they have no expertise on what is going to be needed because they are not the users.

[MoreQARespect]

It's predicting that you will predict wrong frequently enough to make it not worthwhile predicting at all.

I apply the same logic at slots: the way to win is not to play.

>Creating abstraction for a code that was designed without being compatible with these abstraction has a huge cost

I have never found it more expensive to create an abstraction after following the rule of 3.

Indeed, ive always noticed that abstractions which are front loaded are nearly ALWAYS worse than abstractions built with hindsight.

>As I've said, nothing is all white or all black. The problem with YAGNI is the developers think it's all white

We think you're playing slots and remembering only the wins, believing that you're just naturally talented at predicting the future.

Ive seen this attitude in hundreds of devs. They all think theyre uniquely able to anticipate the code base's future needs.

[cauch]

> I have never found it more expensive to create an abstraction after following the rule of 3.

This is the problem: your judgement is biased. You think it was a good idea, but in reality, you have no real idea if it was or not.

Don't get me wrong, as I've said, I think that sometimes not over-building is a good idea. The problem is that YAGNI is the wrong solution. To avoid over-building, the solution is not to invent a rule that says "just don't build". The solution is to stop having developers thinking they know what is useful or what is not.

> Indeed, ive always noticed that abstractions which are front loaded are nearly ALWAYS worse than abstractions built with hindsight.

Again, you cannot know if it is worse or not. You are not the user. It may be good in some cases, it may be bad in other, and I have seen devs saying exactly what you said when their "abstractions in hindsight" was catastrophic.

There is a lot of example, but just one: we built a system that was collecting data, the goal being to accumulate data for months and then analyse it. Few people involved in the project proposed some structure for the data, but the devs used YAGNI to do what they preferred (there was some objection but at the end, the devs just did what they wanted to do, ignoring the rest of the team because they were confident that they knew more than them how to build software). Later, we started the analysis, and realised all the data were crap: the devs kept changing the data structure by building their abstraction with hindsight, without even documenting when these modifications were deployed to the different sensors. We had a mix of data built based on different parameters with no way to know which part was using which parameters.

After the project failure, I saw many devs still saying that they were right to use YAGNI, and being totally oblivious that it's their choice that doomed the project. They were, seriously, saying that it was a lack of requirement, or that the "users changed their mind", while it was not true at all (I was there, and I was not in either side, I just observed), the situation was well known from the start. The problem was they insisted to apply YAGNI as if they understood better than the other collaborators what as needed.

> We think you're playing slots and remembering only the wins, believing that you're just naturally talented at predicting the future.

You literally just said "ive always noticed that abstractions which are front loaded are nearly ALWAYS worse than abstractions built with hindsight".

This is literally you remembering the amount of "win" and the amount of "loose".

> Ive seen this attitude in hundreds of devs. They all think theyre uniquely able to anticipate the code base's future needs.

That's exactly my point (and I'm not a dev).

When you are saying "abstraction is better built in hindsight", you are just thinking you are smarter than other people.

When the situation is that it is difficult to understand what we will need, the solution is to discuss together to understand what we will need. We may get it wrong sometimes, but we will get it right sometimes. If someone just decides to ignore other collaborators opinion and decides "we will need this abstraction", this person has way more chance to be wrong. If someone just decides to ignore other collaborators opinion and decides "we will not need this abstraction", this person has way more chance to be wrong too.

YAGNI is just someone noticing that building a big house without following the plan led to extra work because they have to demolish the bits they've built on next door property, so they decide to build a small house without following the plan.