Wait, I may be confused by the OP's question, are you talking about characters that WE the readers don't like or find unlikable or that other characters in the stories find unlikeable?
Some of my favorite characters in different stories are just horrible bastards sometimes, but I like their characters.
Okay I reread the first post and guess I was approaching it from MY perspective and not the crew's.
Still I think Tev largely misunderstood by his shipmates and even though they've both made approaches towards better understanding each other and creating a better working relationship, their cultural differences are getting in the way. Carol should honestly be more on top of the situation than she's been, of course she's been distracted as of late by Mr. Tall, Dark, & Wicked sense of humor.