"Are you sure you know what you're saying?"

Everyone says, "OK"; but what does that stand for?

Where is the fear factor in the common phrase, "I'm afraid that"?

Is the phrase "to look after" someone / something, based on anything literal? Would this come as a surprise? I.e. to take note of the figurative trail (the token mark) that someone or something has left and just prevent it from working against them, in their best interests? What do you think?

I remember reading this in that old Roald Dahl story Fantastic Mr. Fox:

" 'Have you heard what's happening on the hill?', he said excitedly. 'It's chaos! Half the wood has disappeared...' "

Anyone has read that story will recall that Badger was in a state of dire anguish when he said that; it rather contradicts the idea that "excitement" is a positive and exhilerating thing by default, doesn't it?

Are there words that you claim to be familiar with yet if someone were to ask you what they mean, you just wouldn't be able to explain? For example, this was one that struck me: what does "compatible" mean?

"Compatible (adj.) [...] capable of living together harmoniously or getting along well together; in agreement; congruous; often followed by with.
The poets have joined equalities which by nature are the most compatible. - Broome.
[...] compatibleness, compatibly."
(Webster's New Twentieth Century Dictionary, unabridged, second edition, Library Guild Inc. New York and Toronto 1958.)

Imagine someone saying to you, "Go and be [something]." How would you put this into the past tense? "He went and beed*?"

(Another blog to follow immediately - this one with more reference to foreign language, foreign language terms etc. Thanks for reading!)