[quote name='2Fast']What do people hate about Troi so much? I know people hate Wesley, but now that he's an adult I think he could be forgiven.[/quote]
I don't hate Troi, but her character was ill-considered from the start.
Obviously mind-reading was out of the question, so they gave her empathy. But this led to lots of dialogue that was either obvious ("They're hiding something!" No, really?) or lame ("I sense...something. Strong emotion." Yeah, that's helpful).
This led mostly to her character being a conduit for exposition that was...already completely obvious or superfluous. She should have been a great advantage but how many times did Troi actually make a difference?
Troi episodes also tend to rank toward the bottom of the barrel. "The Loss" (featuring two-dimensional characters that were more interesting than Troi), "The Price" (featuring perhaps the lamest seduction not involving Geordi), "The Child" (ugh). Then there's the Lwaxana Troi episodes. While I enjoy watching Majel Barret and seeing Lwaxana Troi, these episodes tend to be awful. Finally, Troi unfortunately gets featured in many of the "problem with the families" episodes, which tend to have annoying child actors and tedious plotlines.
For a counselor, she is often whiny (see "The Loss") or easily upset or unhinged. Guinan is almost always a better counselor, and managed to get a lot of the scenes Troi should have had. You can essentially sum up all of Troi in three words: counselor, chocolate, and cleavage.
Her character goes nowhere. The most interesting thing she does is go for command, which was pretty brief. The rest of the time she's defined by her non-relationship with Riker, her relationship with Worf, and her earth-mother position of counselor.
There are few exceptions. One is "Face of the Enemy", where Troi is deposited in a situation and has to deal with it. It plays to her strengths and insecurites, and she's able to carry the show. Also, she plays a good supporting role in "Darmok". But these really good uses of her character are the exceptions. And it's pretty interesting to note that the best Troi episode has her off the ship, outside her normal job, pretending to be a Romulan.
Really, did you ever say "Oh boy! A Troi episode!" ? Can you name your top five Troi episodes? Do you even have 5 Troi episodes you can name?