I think Harlan does radio as well, so some of the excitement might be from the need to paint a picture with only the audio for the listener. I'll take him any day over Joe "monotone" Buck any day.
edit: on this video posted in another thread it doesn't seem like he was all that excited about the 4th sack: https://www.buffalobills.com/video/every-bills-sack-against-sam-darnold-week-1