"Get" can mean many things (e.g. "bring," "buy," and "understand," none of which are synonyms), and thus it is a weak, undescriptive word.

Try telling someone to "get something." You will see that that sentence has no meaning whatsoever.

Do you mean they should bring you something?

Should they understand something that they don't understand?

I had an English teacher in high school who would write at the bottom of every paper: "NO GET/GOT! NO -THING WORDS!" I would go through my paper and try to eliminate all instances of the word "get or got," and it always made the sentence/paragraph/paper stronger.

Eliminating (or at least cutting down on) your usage of the word "get" increases the precision of your speech and writing. It is not even a matter of efficiency (in truth, it is more efficient to say "I get it," than to say "I understand the point at which you are driving,"), but by using a strong word in place of "get," you will be able to express yourself more accurately and precisely. I think George Orwell would agree.

Personally, I think it is a moot point most of the time in speech. Clarity in writing is essential because you can't explain yourself with any words other than those on the page.