"Retro" is so big of a category now. But Final Fantasy IX was my least favorite. I have a feeling I'll get some hate for this but:
On PlayStation, the loading times were like 15-30 seconds before AND after each battle, the high random encounter frequency meant you would battle sometimes after every few steps, and monster variation was very low. And running never seemed to work.
So literally 10 seconds of movement, 25 seconds load into battle, battle one of the same 3-4 enemy groups in that area, 25 seconds load out of battle, and repeat.
The story was also very generic. Everyone seemed to love it, but it felt like they played every decision safe to create a nostalgia-friendly experience.
I played it so much but was always frustrated with it. Every time I see someone reminiscing about how great it is, I am just wondering what game they were playing.