1. Data's Death. Okay, so I was kinda alright with his death, because it was a noble sacrifice, and it really was! cry I loved Data for it, because it is something that he would do, a human and android act. Then they went and just made his brother start accessing his memories, thus making his sacrifice TOTALLY MEANINGLESS! Worse than that! They made Data a replaceable character! Like, 'okay the android died, but that's alright because we've got another one just like him with his exact memories'! That is NOT acceptable! stressed The whole point of Data was that he was one of a kind. That he was a member of the crew and as valuable as the "biological" members of the crew.
2. Freaking Director Stuart Baird did not watch a single episode of Next Generation before directing this... this... thing! What is WRONG with you Baird?! scream Maybe if you had, I don't know, done your job the movie wouldn't have sucked SO MUCH. Which leads me to number 3.
3. Nemesis was SO BAD, and did so awfully in box offices, that it led to Star Trek Enterprise being canceled, which in turn led to possibly the WORST SERIES FINALE IN HISTORY! scream I'm not even kidding. Don't watch it. They decided to kill off a main character just because the series wasn't renewed. stressed It wasn't even an episode of Enterprise, it takes place on the holodeck in Next Generation, and makes no sense in that context either.

...Yeah... I was raised by Trekkies.
Janeway for the win!