Robert had before him a big test and spent the weekend complaining about not being able to study because Dominik (~5 at that time) was disturbing him to which i kept responding that he should either lock himself in the office or go study to library.

At 10pm on Sunday, Dominik was in his room with the lights off, but still not sleeping. He was happily chirping, asking/yelling questions at us across the hallway etc. Finally I said: "Dominik, you have to lay down and sleep, and I don't want to hear single word or peep anymore!"
Dominik in turn recommended: "Then maybe you should lock yourself in the office or go to the library -- then you will not hear anything."

I guess what goes around comes around.