I never seem to have a reason to use the Fat Man in the game. I saved up all my mini nukes thinking I would use them in some epic battle. So after I finished all the DLCs and was cleaning the map of Mutant Behemoths, I thought it would be amusing to splode one into a million pieces via a mini nuke.
All I remember was a bright flash after the mini nuke clipped a billboard I was hiding behind on its way to decimate a rampaging behemoth. It was a grand death.
Much better than actually killing the behemoth with the nuke, in any case. He didn't even bleed. Stupid mutant behemoth.