Why is a dangerous word. It's not quite correct to say "never" ask why.

But asking: "Why did you do it that way?", especially if things are not working out, can be confrontational and set an inconsiderate tone

In Scotland the word How is often a substitute for Why.

Why is about Purpose. So, using that word and framing the conversation in that wat will often better results too.

It's all about Consideration*

* to think deeply and explain clearly, always with others' needs uppermost in your mind.