My favourite generation is the one I have nostalgia for and the first one i played, Gen 3
Ruby and Sapphire i think had really good pokemon designs especially my favourite legendary Groudon, he looked metal as fuck on my copy of Ruby. I enjoyed the soundtrack from the GBA version and matched the anime based from it, Pokemon Advance.
What is your favourite generation and why? What details makes it stand out for you?
If I’m answering the question as given, Gen 2 because it was the first games I owned, so that’s certainly nostalgia speaking. However, over the years it’s just so obvious that Nintendo/Gamefreak refused to evolve the series and the variants of the genre are the better games.