1. Yes that’s right (Completely agreed) : we use it when we are full agreeing with someone like we can say 100% agree.
2. Yes you are quite right (Sad Scenarios): when we are sure that he is right somehow but some of the words are contradictory and you have something else to say about it.
3. You are dead right or dead wrong: we use this word when we are mainly in some conference or some kind of meeting where either we get completely agree or completely dis-agree.
4. That’s spot on : we use this word when we are mainly in some conference or some kind of meeting where either we get completely agree or completely dis-agree.
5. You have hit nail on head: : refers to describe exactly what is causing a situation or problem or to do exactly the right thing.
Example: you spotted the flaw mike; you hit the nail on head.
6. You could say so: : we use it when we agreed 70% only with the other party. It’s when someone speaks maximum good but a little different then you know
7. I am afraid so : it is used for politely telling someone that something might make them sad or disappointed.
Example: Did he forget to do that project??? I ‘m Afraid so.