Ah, I see
1)The standard response when you still don't understand what has been explained to you, but simply cannot tolerate any more of the conversation. It must be used
sparingly however, as overuse of "Ah, I see" will lead them to enquire as to what it is that you "see", and then
you're fucked.2)The sarcastic response for when the information that someone expects you to understand is so
vastly complicated and pointless that you could slap them out of sheer frustration. Usually said with more emphasis on the "see" part of the phrase.