I don't understand why so many male Star Wars fans — at least here — seem so intent on Rey having this horrible bad side to her.
It boggles my mind.
First well executed female Jedi in the trilogy? Succumbs to the Dark Side of the Force in the next movie because "Lol, women and emotions, amiright? Huh, huh?!"
Rey was certainly tempted by the Dark Side during her confrontation with Kylo, at least that's the read I got on it, but that's par for the course for the Force Sensitive heroes in Star Wars. Luke used anger to best Vader in Jedi, then rejected the killing blow. Rey used anger towards the end of her fight (it was after she focused her mind and started fighting back from the cliff, and wounded Kylo), but, much like Luke, she rejected the killing blow. She could have done it before the earth opened up between them, when she did the overhead downward swing then kick that knocked Kylo to the ground. But she didn't.
I just don't see a Dark Side trajectory for her arc. I see someone who, much like Anakin, is incredibly gifted in the Force (and if Anakin is her grandfather, it makes sense as well). I see her journey paralleling Anakin's and Luke's in that she is older and untrained, with a lot of emotional baggage to sort through. Way more than Luke ("Wah, mean old Uncle Owen won't let me go to Tosche station to pick up some power converters!" vs. "My family abandoned me on Jakku under the 'care' of some scumbag named Unkar Plott who forces me to scavenge for goods, then clean and scrub them, then swindles me out of my gross moldy dehydrated sponge bread loaf.") Rey has some shit to deal with that makes her very interesting compared to Anakin and Luke. Anakin chose to leave Shmi and become a Jedi. The tragedy for him is that by the time he comes back to her, she is dying. Rey's sad, lonely life is much more tragic. Anakin at least had Obi-Wan, who viewed him as a brother, even when the Jedi Councils were being twat-waffles to him. Luke had Owen and Beru, who, while strict, clearly loved him. Rey had...Rey. And the hope that her family would come back is what gave her the strength to put up with Unkar's shit. It's just really freaking sad.
I'm interested to see how she handles that past once she's with Luke. Doesn't mean she'll go Dark Side, only that it adds a lot more tension to any scenes in which she is tempted by the Dark Side, because they will truly be tests of her character. Tests that I think she will overcome.