I just finished the latest volume of A Livid Lady’s Guide to Getting Even and Elizabeth is a great example. She is the stereotypical "crown prince's fiancee is getting dumped because a commoner girl come noble is buttering up to the prince and throwing false accusations at MC until the prince throws her into jail for bullying his true love". Seriously the initial setup is so cookie cutter that I wasn't sure if I really read a new novel...

Anyway, where the series starts to differ from the dozens of others with how ruthless MC is in getting her revenge. While mostly a hyper-competent goodie-two-shoes princess in exile character, when she starts her revenge plots she becomes a monster that has zero concerns with sacrificing innocent civilians. An example from the first volume would be her consciously putting an enrage spell on one of the prince's cronies knowing full well that he will ultimately go on a killing spree in town before the guards can stop him.

I find her generally off-putting as a character since she is written so inconsequent. For 3/4 of the volume she is saving poor civilians, slaves, and children left and right just like any other MC character, and then suddenly she turns around and makes plots that would kill possibly hundreds of innocents. I don't dislike ruthless characters but they should be written believable.