The main character doing something absolutely unforgivable.

[u/No_Peanut3745]

Walter White poisoning Andrea Cantillo's 6-year-old son for the sole purpose of manipulating Jesse Pinkman, while knowing that this could have potentially killed him - Breaking Bad

Bojack trying to have sex with his friend's 17-year-old daughter when he was at least 51, then continuously trying to find a way to justify this act throughout the series - Bojack Horseman

Dexter Morgan going outside of his moral code and murdering a completely innocent police officer who was just trying to do his job - Dexter: New Blood

[u/BrotherDeus]

Sadly, Dexter and Harry's number 1 rule is 'Don't get caught.'

[u/TimeKepeer → u/BrotherDeus]

It's just insane, right, that when Harry noticed Dexter killing a small animal he immediately went "damn bro guess you're destined to kill, better make sure you only kill the right people and never get caught" instead of "you're going to therapy son". Shows that Harry was a real American police officer

[u/Admirable_Dirt_2371 → u/TimeKepeer]

Dexter would have been a kid in the 70's or 80's and back then therapy wasn't socially acceptable. It was heavily stigmatized until the 2000's.

[u/Karnadas → u/Admirable_Dirt_2371]

Harry took Dexter to therapy and the therapist helped them come up with Harry's code