I second this. I sometimes notice people talking to me and repeating the same thing 3, 4 times, just with different words. Please! It gets on my nerves a bit. Say it once, I'll ask if I don't understand. If you need me to understand, and want assurance that I have, repeat it twice and feel free to ask 'Got it?'
I think some of this problem could be averted by better communication skills on our part. If I notice someone repeating something to me, maybe it means they don't think I've gotten it, so the best response would be to say it back to them in my own words. I've found this technique to be marvelous when I can remember to use it. ;)