Wow, I can't believe I haven't ever seen this thread before. I need it because there are quite a few things that make me want to bang my head against the wall about Roswell, quite a few that have already been mentioned.
I have to agree with everyone about them bringing up storylines and just dropping them out of the blue, sort of like what they did with some characters. For example, what the hell ever happened to Sean DeLuca? Not that I liked him, because I sure didn't, but he was there in season 2 causing more trouble for Max and Liz, and then we just never see or speak of him again. And where was Brody in season 3? As for storylines, they were probably the worst about doing that kind of stuff in season 3. There were so many good stories they could have told that could have possibly staved off cancellation, and yet we were usually subjected to crap.
Another thing that always bothered me was the Max and Tess sex, and not just because I'm a diehard Dreamer. We know that Max was walking around with a condom in his back pocket, and that he was always characterized as being a cautious and careful kind of guy, and yet he and Tess just happen to have unprotected sex. WTF!? Sometimes, the writers would just do things that made absolutely no sense.
I suppose though that my biggest problem is with Season 3 altogether. For some reason, even though the cliffhanger of last season had to do with Max and his son, and sort of his relationship with Liz, they switched the focus of many episodes of season 3 to Isabel's relationship with Jesse, who just came out of nowhere. That didn't make sense to me at all, and frankly made for some very boring episodes imo. The other major problem with season 3 was that it seemed that all the characters were out of character. They had Max and Liz robbing a gas station, when that's the kind of impulsive thing that Michael would do. Then Isabel and Michael didn't seem to care that much that Max in Liz were in jail and going on trial, thus exposing them. And then you have Maria just flip flopping on bieng in the Alien Abyss, and breaking up with Michael when she had been the pursuer in the last two seasons. And finally, you have Valenti being a completely lazy bum, letting Kyle pay all the bills, playing in a band, and dating younger women. And that's not to mention how the parents finally decided to take an interest. All I could say for the season was WTF.
I know there's probably more, but this is gonna be a long post as it is, and I really can't think of anything else at the moment. BTW, sorry for the longness of the post.
~Dani