That's good

A filler for a conversation used to show response to a person's story with some interest. A listener may like the person, but this response is Often given in response to a subject that is complex and/or the person listening does not know a lot about such as a story. Used in place when listener does not want to look ignorant or does not know about subject to make an depth analysis.

Example;
Father; I just fixed the lawnmower. It had a special motor and I replaced the value along with the spark plugs. I went to the store and check the appropriate department and they had it on sale. I am looking to get some special fuel. It should work great

Son; That's good dad.