That's not right if the speaker is speaking from the perspective of the moment of speaking.
I think you mean I don't think we needed to do it.
I might well not know what I'm talking about, but I don't think it's what I meant.
Glizdka,—if you're sure you want to use need instead of should (there is a difference of course, another option is We needn't have done it, without the 'I don't think' preface.
I don't think
should conveys what I'm aiming for.
Should feels like just my better judgement in hindsight, but I also want to include "This was unnecessary."
Imagine we had the game in the bag, and, if we had slowplayed it, we would've won, but because we were being impatient, and felt like we could win, we made a move that ultimately made us lose the game. We now know it was better not to be done.
I guess I want a bit of
shouldn't have and
didn't have to in this sentence. Does
needn't have have that meaning, in this context?
I'd say that technically, I don't think we need have done it is in fact correct grammatically speaking but it would sound wrong (or odd at the most) to most native ears, I think.
I've been reading on cases of normal verbs behaving like modal verbs, eg,.
need,
dare,
say. From what I've read,
need needs to be in a negative sentence to be used like a modal verb, so basically
needn't.
I'm trying to bypass
needn't by adding a negative preface, as you've noticed.
So the sentence is, technically, grammatical, albeit it feels awkward because
need still needs to be in a negative sentence, right?
"I do
n't think we need've done it." → "I think we need
n't have done it."