could not have been more disappointed

[keannu]

Is this "[FONT=맑은 고딕]could not have been more disappointed[/FONT]" a presumption or counterfactual utterance? I think it's presumption, but it's kind of confusing. I think a similar example is "It couldn't be better".
I have always been a huge fan of Redbug Cameras. However, when I purchased your newest model, the Superimage 2000, I could not have been more disappointed. I acquired it on June 3rd of this year and it does not function correctly. The camera lens does not focus properly and the resulting photos are blurry and unclear. I went to the local service center to get it repaired, but the poor service I received there only complicated the problem. I am extremely frustrated with the poor quality repairs that were made in addition to the overall inferior quality of the camera. I insist on receiving a full refund. Enclosed is a copy of the original receipt and the repair bill.

 

[SoothingDave]

She was not happy with the camera. Her unhappiness was at its maximum level. There was no way she could have been more unhappy.

 

[keannu]

I remember Raymott said that "could" can be used as a less blunt way to say your opinion. And this seems to be so as it's different from "I couldn't be more disappointed" which express your feelings quite directly. If my interpretation is wrong, please let me know.

 

[abaka]

This is a different usage of could, a contrafactual, hypothetical, or subjunctive one. To amplify SoothingDave's excellent reply:

In the present: I am unhappy with this camera. I could not be more disappointed with the camera. (No matter what the reality, even if everything changed I would not be more disappointed with the camera.)

In the past (as in your example): When I purchased your newest model, I could not have been more disappointed. (At that time, if everything had been different I would not have been more disappointed with the camera.)

 

[keannu]

Thanks a million!!! The reason I was confused was it's an imaginary result in a hypothetical(counterfactual) conditional. In such conditional clauses, only counter-factual things are supposed, but the main clause of imaginary result can have give nuance of likely things. Anyway, the imaginary result is something that doesn't exist.