A common complaint I hear a lot and I screech about is Yui's "stupidity." But is she as stupid as I screech about?

Fight, Flight, or Freeze

Humans usually do one of 3 things when in danger: fight, run, or freeze.

As we can see throughout the anime, Yui either runs when in danger or freezes. Which isn't a bad thing, it just makes her human.

Humans VS. Vampires

In Diabolik Lovers, vampires can teleport and are incredibly strong. And Yui's just an average teenage girl. Yui knows if she tries anything, it's only going to cause her more pain.

Analysis?

So, on one hand, this could mean she is secretly really smart and everyone mistakes it for stupidity, or I'm just reading too far into this.

I wouldn't be surprised by either.

Wow, this was short. Oh well.