Knowledge of Upcasts (Counterspell)

@OP, you're being quite generous already by naming the spell. I got with, "so-and-so is casting." I wait a beat, and if the reaction isn't immediate, the spell goes off...

Quote from SagittusRectus >>

Oh my. That's a much, much more powerful Counterspell. Now I need to gin up some wizard duels.

 I'll note that a lot of people disagree because a lot of targets have high Con saves. However, I'm quite a fan of this version. 

I'll note, for this conversation: While 5e has the ability to identify a spell being cast (thanks to Xanathar's), 3.5e had the ability to identify the spell and counter in the same Immediate Action (though Counterspell was much trickier back then).