Star Trek Voyager 7x13 - Repentance
The show doesn't usually touch on the things Seven has done and made to do as a Borg drone. And Seven also almost never talked about how painful it is to become a drone and have implants installed in her body.
As we've seen from previous scans, Seven's occipital implant required removing half of her skull. Seven was probably still a child at that point when the procedure was done, a teen at most.
I like that the episode started with Seven not being sympathetic to Iko, who started as an unrepentant killer but by some hand wave sci-fi nanoprobe, Iko began to feel the weight of his crime. By the end Iko and Seven bonded together. This is a part of Seven hasn't shared with anyone apart from Captain Janeway but also it's not something Seven liked talking about.
The only other time Seven talked about this was when Neelix asked in Memorial and she was a little brusque in her response because she really didn't like to talk about the horrible things she's done for the Borg.
Seven has come a long way from the time B'Elanna asked her if she felt terrible for what she's done to easily diagnosing guilt in another person because she lives with guilt every day. Guilt and remorse are old friends to Seven.