I really like morally complex characters over cut and dry "good" ones.

Tamlin in ACOTAR is the best fucking character in the entire book series and I will fight you. He's not in the right, he's not in the wrong, he is in this moral and ethical gray area where he clearly wants to be a good guy, but also greatly lacks a lot of social awareness. He has anger issues, struggles with a lot his own demons, and fails to make life good for the protagonist of the book series (Feyre Archeron.)

He makes a lot of misguided decisions across the whole book series, but he always has good reasons. At least they are good reasons from his perspective. He makes his mistakes, he acts like an asshole at times, but in the end he ends up risking his own life to save Feyre and ends up accepting that she no longer loves him.

He's a great character. I absolutely love him.

EDIT: Especially compared to the other characters which can basically all be described as "good people who are so nice that they end up making bad choices sometimes."