Catullus: Poem 85
Odi et amo. Quare id faciam fortasse requiris.
These two lines are so well known that comment would seem almost unnecessary, but there are inner nuances. The first three words are flat and blatant, a confrontation of opposites whether literary or psychological. (Note that odi as a defective verb has a rationale: HATE is a "perfective" state which simply exists, there are no tenses to it or time-frame. Hence completely unlike amo!) Now the first line lapses into an ultra-calm and clinical mode: You are my shrink, you ask my purpose in this difficult situation of my making......
Answer: I haven't a clue!....but I know it is going on.....(all just as calm as the interrogator's question).. and.....(bursting forth with one word of searing pain:) I am TORTURED. --- We have a problem of course with excrucior, which is so good in English as "excruciated" but remember this is the Roman world where the cross is the instrument of real torture, not psychological pain in the modern sense. So think back to the procedure!
Aside from the hate/love premise, the poem gets its point across by violent shifts of mood, starting with a statement, then a curious psychological inquiry as to motive, next a bland admission of incomprehension, leading to statement of fact, and exploding into that last word. Note excrucior gets an extra thrust from its four syllables in a matrix of 2/3's. I have found in doing a class exposition of this poem that I could get the effect I wanted by reading the lines in a flat voice, slowly, and then to the class's amazement screaming out the word "excrucior". Then I had their attention!
ODI ET AMO. Quare id faciam fortasse requiris.