I robbed his vault and killed all his guards (damn those golems take a long time to kill!).

 

Then I stole his robe. Later when he asked for me, I admitted to robbing the vault. I told him straight to his face.  Now about his robe, I NEVER expected the developers to actually add in him reacting to this. But he recognized me wearing his robe. Then something about "his nails burrowing into the chair" or something. Man this was too good... I was quiet literally laughing so hard I was crying at this meeting. Arkemyr must have the world's greatest restraint. I not only robbed his vault and murdered his guards, I straight up told him to his face while wearing his robe xD    

  

Ahhh... I know you guys probably knew that was possible but just wanted to share how much I enjoyed all that.

yeah, there's a few nice reactive touches with items/gear that pop up like that.

 

another example is: (minor-spoilers) if you have concelhaut as a pet equipped while doing Forgotten Sanctum DLC, you get some extra interactions between Concelhaut and the other archmages.

You can also have your companions put on the robe and lie to the imps and talk to Arkemyr. They each have their own lines, Aloth does a pretty good impression when talking to the upstairs imp.