When you feel like getting into fights easily instead of trying to find a dungeon. Or go into there with a few friends and try to kill ghast's or those flame monsters that I cannot remember their names that spawn in fortresses (y u no work, brain?), which aren't in beta 1.6. Just the adrenaline of being chased down by a ghast is awesome, especially with friends. I think it's that knowing that you could die at any time is why I can't wait to go to the nether. I like taking risks
PSN-Aadrianseth 3DS FC: 0817-4248-5560 PM me so I can add your FC. Warning: I start posting some weird stuff when I'm bored. You have been warned
My number one reason for going into, and exploring The Nether...
Jump Gates. Build a Nether Portal in the right place, far enough away from pre-existing Nether Portals, and you can spawn Jump Gates all over your Overworld, allowing ultra-fast travel all over the world, using The Nether as Subspace.