Rachel and Tommy as characters are what ruined season 4 for me.

Rachel orchestrating the rape and showing no remorse for what she did or the aftermath was just way over the line. Obviously she has done evil things in the past, but along with many others here in this sub, I just had a sick feeling in my stomach from when that happened midway through the season onward (the finale ending helped a little, but it ultimately fell well short of the transformation we desperately wanted to see in her). I agreed completely with Quinn in that midseason episode, when she finally put her foot down and was disgusted by Rachel's actions and complete lack of empathy.

And Tommy... he felt really shoehorned in this season. Where did he come from? All of a sudden he comes in as a producer, and has a relationship with Madison and Rachel (obviously he and Rachel weren't a couple yet, but there seemed to be clear lovey-dovey vibes from the beginning). I really didn't like how he turned out to be every bit as evil and crazy as Quinn and even Rachel. Those two ladies should be in a league of their own, and nobody should just waltz in and get on their level so quickly. We found out Jeremy was crazy in season 2, but he was good at first, and we got to see Rachel messing with his head until he cracked. Tommy just seemed to be made into a Rachel clone/wannabe as a plot device for Rachel to see how terrible she was in the reflection, not to mention him being the scapegoat so Rachel (and Quinn) to get off Scot-free yet again.