I am not sure if anyone has mentioned this here, since it is hard to dig through more than 900 pages. In Skellige, if you've dealt with Morkvarg before you and Yen went to Freya's garden together, they would have a different conversation.
Yennefer: You didn't mention your heroic battle with this Morkvarg character...
Geralt: You know me... Don't like to take my work home...
Yennefer: Mhm, I'm afraid you don't like home - the very concept of it. I asked you once to move to Vengerberg for me. Remember? Was that ever a row...
Geralt: Yeah... Those were the days...
Never knew this, need to try it next playthrough, again