Some people like a challenge
We never managed to do Sartharion with 3 drakes, or 6 minute Malygos, or the 4H kill them all simultaneously achievement, etc.
Ulduar has even more crazy hard modes.
Basically you can defeat the content without THAT much enormous difficulty I presume but the hard modes will definitely be hard.
For example, we beat the first boss in Ulduar before the servers exploded but we tried him the first time with his towers up (hard mode) and got reasonably shit stomped.