disappointing
The view was nice, but the food was really disappointing.
pity
It's a pity that you can't come to the party.
unfortunate
unfortunate person
unfortunate accident
It's unfortunate she lost all of her date from her PC.
despair
The new employee was in despair about his failure at his work.
I don't think I can make new robots any more.
I don't think that will work.
I'm afraid I disagree. I have a different idea. I'm not sure that's good idea. I don't think so.
I don't think we can finish it in a week.
I don't think this restaurant is good.
Not at all.
We don't always win.
We always don't win.
What do you mean by that? I can not quite grasp what you want to say.
How do you mean? Could you elaborate a little?
Why do you say that? It's not very clear to me, I'm afraid.