The "that's better" button

I'm not sure when I realized this, but a while back (maybe 2-3 months ago after we moved to the new house), I was watching Colin play with the radio. Colin would push the volume up button and say "loud" and then push the volume down button and say "that's better". It was then that I realized that he thought the volume down button was called "that's better". He was just reiterating what I would say everytime the volume was too loud and he would turn it down, ... "that's better"!