Ocarina of Time. The Zelda franchise is far and away my favorite game franchise. I was 6 when the original LOZ was released in the US and ALTTP was transcendent for the SNES so I was ecstatic for the first 3D Zelda.
Maybe it was because I was used to much harder games and was at my gaming peak, but it just felt a collection of giant, empty rooms with virtually no challenge. People still rave about it, and all I remember is the disappointment I felt from it being so easy compared to pre-internet LOZ and ALTTP.