Star Trek

V'ger

There seem to be a couple ways to answer this.  One is to compliment the writers and actors and give a character (normally villainous) some cred as "working".  Kai Winn would be my top pick.  The characterization and performance made her one great villain that almost turns my stomach when she comes on screen.  She's definitely love to hate

The other way is to point out when writers, actors, or both just didn't get it right.  A failed or failing character whose presence takes away from the pleasure.  Here I am not on board with others as I do like the oft-loathed Wesley Crusher and think that character brought some interesting facets to the show.  I actually like Neelix and Kes a lot too.  For me, in this category are many of the Voyager characters (which is probably why I don't watch that show as much).  So, here's my short list of my HATED VOY characters: the Kazon (all of 'em, never were convincing baddies IMO), Paris (Riker lite), Kim, Tuvok ... most of them just didn't seem well developed.  It's as if they decided that DS9 would feature the character development and VOY would only have space adventure.

worf's predecessor (we shall  not speak her name)

pulaski

wesley crusher

Beverly Crusher. You put her up against McCoy, or the Doctor, or Bashir, or Phlox & she looks pretty damned pathetic. How the heck did she become a CMO? 

Louse Fletcher is a fabulous actress. She did well to assume what was a very melodramatic/ Shakespearean role. Of course this doesn’t stop the character from being annoying. I used to groan (loudly) whenever Kai Winn ‘popped in’ for a visit on DS9. Her smug, arrogant, jealous, intensely ambitious nature is enough to grate on anyone’s nerves. She was however, strangely compelling; especially when she ‘got down’ with the Pah-Wraiths. 

Keio O’Brien I found tedious. Partly because of Chao’s hammy acting, I personally found the episode ‘The Assignment’ hilariously bad. Also, they had her character do stereotypically Japanese things all the time, like trimming Bonsai trees and making tempura. 

Wesley, obviously. Will Weaton was cool on Ben 10 as Darkstar, though.

I also think Rikers wife..Diana Troy? is also pretty annoying

I hate Admirial Nechayev. Captain Jellico sucks too.

Alexander in the Next Gen series that kid killed me on episodes only somewhat good one is when he came from the future to train or kill his self

Worf

A friend and I made up a list of the All-Time Top 10 Fictional Characters We Love To Hate. (All different movies and TV shows, not just Star Trek). The top 4 (as follows) were from Star Trek.

Nero

Borg Queen

Kahn

Lore (I actually haven't seen Lore at all, but I have seen Data and he is very likeable, so logically, as Data's evil twin, Lore must be proportionally hateable. At least that's the theory.)

Lore's kind of like Data with the personality of Arik Soong from ENT.

Kai Winn

Neelix

Tasha Yar... terrible. Good riddance season 1. 

Oh... my... gosh... she is the evilest person EVER!!!! I hate her! She is such a snake! I also have this thing against Deanna Troi, She is such a wimp.

Think about though -- is it hatred for Winn (as in for a badly portrayed character), or do you love to hate her? No wurries for either answer. I didn't like her at first, but now I love to hate her.