I have a bit of a headache.
What's the problem?


To use "What's the problem?," the other person in the conversation must make a statement alluding to a problem, but not openly stating it. For example:


A: Oh, this is bad...very bad! (looking confused and searching through their pockets)
B: What's the problem?
A: I think I lost my car keys.


Saying "What's the problem?" without this setup in place, the expression come across as aggressive.


"Calm down"! & "Take it easy are" are also usually used incorrectly.





EXPRESSIONS FOR CONVERSATION AND PERSONAL COMMENT    
(1)  When you start saying something
                    contributing to a conversation
                    making a contribution
     
     First of all, I would like to say/state that.............
     To begin with, I...................
     In the first line, I.............
(2) What can you say instead of "I think" (don't sink, please)
     I would say/think
     In my opinion
     To my mind
     I am of the opinion that
     I hold the opinion that
(3) When you want to stress your "personal opinion":
     Personally I think
     As far as I am concerned
     As for me
     As I take it
     As far as I can see
(4) When you "agree" or when you "don't agree":
     I entirely/quite agree with you.
     I agree to (with) her plan.     
     I am of the same opinion.
     
     I differ from/with you entirely.
     I disagree with you: I am sure you're mistaken.
     I stick to my opinion.
     Let's agree to differ!
(5)  When you want to say the "opposite" of what someone else 
     said:
     on the contrary! quite the contrary! just the opposite!
     That is the very opposite of what I said.
     That is quite the contrary to what I said.
     I maintain the contrary.
     In contrast to what you said, I maintain that...........
(6) When you are "quite sure" of something:
     of course!
     That goes without saying (It goes without saying
that......)
     I contend/maintain that................
     It's my conviction that..................
(7) When you want to "ask a question":
     May I interrupt you?
     There arises the question/point whether/if......
     This question raises the whole issue                              
(8) When you "haven't understood":
    I beg your pardon. / Pardon?
    Could you repeat what you've just said? But slower, please./
    Could you slow down a bit?
(9) If you should want to "correct a mistake":
    Excuse me (for interrupting) you should have said:"....."
(10)When you want to "distinguish" (make a distinction between) 
    two aspects of a question, when you want to distinguish one 
    aspect from the other:
    on the one hand                 on the other hand
    in general                      in particular
    generally speaking              
    on the whole
    taken as a whole
    at first sight                  on second thoughts
(11)When you want to "add" something:
    
    In addition,.........................
    Moreover,....................
    Furthermore,........................
    Finally,...........................
(12)When you want to "emphasize" something:
    I would like to lay (put) emphasis (stress) on the fact
that..
    I just want to point out that................
(13)When you want to "say the truth":
    To be frank (with you),...................
    Frankly (speaking),.........................
    To say the truth,........................
(14)And if you are "not sure":
    I don't know exactly.
    I don't know for certain.
(A) General phrases:
    in other words                    in this respect
    to a certain degree/extent        It depends on your point
of
    in brief/short..........                                view
    To be brief,..................
    To cut a long story short,......  Let me put it this
way:....
    I don't know. - I don't know either.   Nor/Neither do I.
(B) Common Abbreviations:
    e.g. (=exempli gratia) = for example, for instance
,etc. (with a comma in front of it) = and so on
i.e. (=id est) = that is (to say)