"Oh no, here we go again, he is starting on his pet topic....."?

Do you have someone in your vicinity who is always and always talking about his/her pet topic, to the point that you go: “Oh jeez, here we go again….I really get sick of it”
No need to name names of course, but can you tell their topic?
I have a colleague who had a career in social housing maintenance and every damn time I work with him he starts babbling about, throwing in social housing maintenance lingo.
On top of that he is very longwinding.
You know someone like that?