I find it extremely difficult figure out if it should be referred to as the past or the present.
Like when Elaine says “That is …”, to me, the performance has happened, and it should be considered as the past. But there is no such thing as clear cut.
So, “past” or “present”? This is really killing me.
We don’t want it to kill you! If someone says something to you which you think is clever, you can say either: That’s a good idea or That was a good idea. It depends on your perspective. If you say: that’s a good idea, then it (the idea) is still in your mind and you are thinking about it. If you say: That was a good idea, then it (the idea) was in your mind and you have moved on to another idea.