Yes actually that was the idea I wanted to express with 3. It is somebody's pet phrase and you use it while talking to him and you want to point put that it is his pet phrase. (You might just be using it because that is the phrase that has come to your mind, or you might be pulling his leg about his pet phrase.)
You have it exactly - either of those reasons might be why I would say "as you say."
For example, my husband tends to say "It is what it is" as his way of saying "don't let this bother you." So when we were talking about something the other day that usually would have upset me, I did say "Well, as you say, it is what it is."
On the other hand, if I was just teasing about a pet ph
It is very nice of you. I'll try not to offend anyone. Your husband is a wise man. That is really good most of the time, but then again, there are times when it becomes difficult to put up with wise people!