I had to collects the parts to Mehrunes Razor for some guy opening a museum in Dawnstar I think it was. At the end I was given the option by Mehrune Dagon to kill the guy and keep the razor for myself.
The poor bloke says let's just go back to the museum and we can share some money because he has a family and just wants to open the museum and I blasted him off the mountian with a dragon shout [never gets old]

.
I felt so awful for ages afterwards that I'm actually considering changing my character to a good guy and doing some healing and pilgrimage related stuff.
Unreal. That's art right there.