The one that really got me stuck as a kid was the Forest Temple. I would get the bow, but then I'd be stuck because I'd be missing one key. So I'd go clear all of the overworld, all of the Fire Temple, all of the Water Temple, then eventually go back to the Forest Temple, which would still be blocking me from becoming a child again.

Eventually, after a few weeks of that, I noticed that I needed to drop down one of those seemingly endless pits that you'd get access to, after hitting those eye targets with the bow. I had instinctually avoided those holes, thinking I'd just void out if I fell in them. Over a month stuck in that game, just to find out that it was that simple. Everything else went smoothly after that.