Explanation on what can go wrong if Hooks were called inside loops or nested functions?

The Rules of Hooks section states that the first rule of Hooks is to only call hooks at the top level, i.e. "Don’t call Hooks inside loops, conditions, or nested functions". Later in the section, it explains what happens if we put a Hook call inside a condition. This still leaves me with some questions/doubts though. Are there examples where something can go wrong if Hooks were:

• called inside a loop?
• called inside a nested function? Furthermore, isn't a custom hook just a nested function? 🤔

I've tried to dig into some related questions on Stack Overflow here and here, but the answers provided only give the correct examples, but not the incorrect ones.

Could you provide incorrect examples for the other two cases? Or at least a little bit clarification would be most appreciated. :)

Empieza por la sección Rules of Hooks, especialmente por la explicación existente sobre las llamadas condicionales a Hooks. Añade ejemplos incorrectos o aclaraciones que cubran el uso de Hooks en bucles y funciones anidadas, incluido cómo se diferencian los custom Hooks, y considera terminado el trabajo cuando estos casos estén claramente explicados en la documentación.