This another part of my multi-thread Laurel dissertation.
One of the reasons Laurel was so frustrating is that she was never allowed to be the complicated character she actually was. We would get moments throughout the series but they were always explained away rather than incorporated into her character. She didn't like Tommy because she thought he was trying to buy her love and not because she was with him to get back at Oliver and was annoyed that he had actual feelings. She said some awful things to Quentin and Dinah in seasons 1 and 2 but that was because she was employing tough love and then drunk/high so no harm done. Her animosity towards Sara was completely earned and should have been a long term story but was wrapped up quickly because the decision was made to kill Sara. Nevermind that it would have made her rage and Single White Female story of season 3 that much more interesting. She wanted to be a vigilante but never thought about quitting her job, the risk she was taking with regard to her cases, or showing any signs of difficultly in managing the two.
One of the worst things Laurel did was put Sara in the Lazarus Pit. She wanted Sara resurrected, and that was all that mattered, so she ignored everyone telling her not to and then acted like the soulless monster who emerged was no big deal. That should have been a major crack in her relationships with everyone yet was forgotten the second Constantine restored Sara's soul.
The show never went deep on the complexity they set up for her. The line about letting the darkness in should have been a turning point for the character but was retconned a year later with Felicity's horrible line at Sara's expense. Why make it either or? Why not have the darkness be the start of Laurel letting go of her life plan and realizing that life and the people in it are complicated? I'm not suggesting they should have made her a villain but pretending she was a goody two shoes her whole life and then elevating her to sainthood when she died was a major disservice to what was set up. Laurel as written was extremely complicated: she had a terrible relationship with her sister long before having an legitimate reason that seemed to stem from being their parents favorite child (which she knew and enjoyed), she decided at a young age that one of her life goals was to become Mrs. Oliver Queen and purposefully turned a blind eye to who he really was, and she cared so deeply about her reputation that she; turned away from her plan of corporate law because she worried it was going to reflect poorly on her, she only accepted Tommy's help with CNRI because the continued refusals were starting affecting how her colleagues viewed her, her anger at Oliver cheating seemed to only be about the Gambit rather than all the other times and that was equal parts everyone knowing and it being with Sara who she viewed as beneath her.
For me, few things annoy me more than a show that has a disconnect between the character they think they've written and the character they've actually presented. I loved the Gilmore Girls revival season because it was the only time they were aware that Rory is an awful person and wrote her accordingly. I loved season 5 of The Vampire Diaries because, again, there was an awareness that Elena wasn't the Compassion Queen but was instead a master manipulator and so much like the lesser than Katherine. They even had Katherine possess Elena's body for weeks before anyone realized what had happened. I am all in on that kind of storytelling. We got this for a little while when Black Siren first showed up but then they clearly got bored and went with instant redemption and glossing over her crimes and the character stopped being interesting. This show had so many opportunities to follow through and make Laurel one of the most interesting and complex characters on television and they squandered it over and over.