Lanyru Mining Facility. I hate that place. I hated the bos to. I mean, it wasn't even a boss! You fight the same thing at the Sandship and that time it dosen't even give you aHeart Container! Plus it's way to easy to kill.
I hated how they reused Ghirahim as a boss again. They should have had something different and had Ghirahim try to stop you from stopping the Imprisoned the second time. Also, the second stage of the Imprisoned was really annoying. You miss once, and you're done.