What's that one little feature or mechanic of FNV that just annoys you?

I find it annoying that you can't make Nuka-Cola with a Nuka-Cola bottle!

But you can with an empty soda bottle?

Empty Nuka Bottles are used to create Purified Water at the Sink.

Unfortunately, the Lawyers for the Nuka Cola Corporation were turned into Ghouls, so they kept sending out Cease and Desist letters to people making home brewed Nuka Cola. Especially as they don't have the 17 fruits used to make the flavor extracts that the real soda uses.

The whole crafting system needs more work, it's not much fun to use as it is now. There should be a little info box like there is for weapons which tells you what recipes an item is used in. It also shouldn't eject you from the menu every time you make something.

The fact that if you turn off the HUD you also turn off the crosshairs. I'd like to turn off the HUD but would find constantly grabbing the wrong item extremely annoying.