[Grammar] Only if - coma or not?

[Charlie Bernstein]

Now it's obvious how good my English is: my comment was not to be sarcastic or humorous, but one that expresses shame and is to be taken plainly .

Thank you for explaining. I'm sorry for misunderstanding you. Your comment about sackcloth sounded like extreme exaggeration, which I misread as humor.

Please don't feel ashamed. You did nothing wrong!

 

[Barb_D]

As Charlie said, it was far too extreme for simple mistake like coma/comma.
If you had said "Oh, I'm a little embarrassed about that" no one would have thought you were being sarcastic of funny.

You chose an idiom that was such an extreme expression of mourning that we assumed it was sarcastic.

 

[Fear not only believe]

That's probably because there is a very similar idiom in my language, so I thought they meant the same.