I tried vibe-coding few years back and switched to "manual" mode when I realized I don't fully understand the code. No, I did read each line of code and understood it, I understood the concepts and abstractions, but I didn't understand all nuances, even those at the top of documentation of libraries LLM used.

I tried minimalist example where it totally failed few years back, and still, ChatGPT 5 produced 2 examples for "Async counter in Rust" - using Atomics and another one using tokio::sync::Mutex. I learned it was wrong then the hard way, by trying to profile high latency. To my surprise, here's quote from Tokio Mutex documentation:

Contrary to popular belief, it is ok and often preferred to use the ordinary Mutex from the standard library in asynchronous code.

The feature that the async mutex offers over the blocking mutex is the ability to keep it locked across an .await point.