Was definetely the jungles, though in 10 years you eventually learn the routes more or less(not so much Yhoator <_<). In Yorcia I have no idea where to go, and in Arrapago too.
I have Arrapago Reef pretty much memorized due to farming Zeni over the course of 2 mythics, but it's still an annoying zone (albeit cool one).
Yeah, the jungles rate fairly high up there. I was going to say my worst time was running on foot from Windurst to Jeuno for the first time (I mean
the first time) as a newbie. No gil to buy silent oils or prism powders. It was simply just a very fearful experience.
But honestly, it was being left stranded in a Yhoater exp party without a warp scroll. Everyone brought theirs but me (fail). So, not only was I lost but I was also without silent oils and prism powders. After about an hour later trying to make my way back to Kazham on foot, it came down to running up behind a Goblin Smithy who was blocking the path. I had a 50/50 chance on which direction he was going to turn to go back. I picked correctly and survived. Zoning into Kazham never felt more satisfying.