These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Basic Instinct
Alternative Character Interpretation: There is much debate amongst fans of the film whether Beth is an innocent victim or an evil Femme Fatale.There are people who think its not a hundred percent clear even at the end that Catherine is a murderess. There is even a theory that Beth and Catherine are in league all along - which explains how they can guess each others actions and know how the same information - and only pretend to be foes to mess with Nicks head. Did Roxy commit any of the murders? Apart from her brothers and the attempted murder of Nick. The final shot is interpreted differently by different viewers. Is Catherine about to kill Nick? Was she going to kill him and then changed her mind? Does the ice pick mean she definitely is the killer or is it only supposed to hint she might be? There is also debate whether the first scene of Nick and Beth in her apartment is sex or date rape.
Interestingly, we never see Catherine commit any overt or violent act (apart from scratching Nick during sex). Both Beth and Roxy act with violence toward Nick, but we only see Catherine remain passive throughout the film.
Fridge Logic: The pantyless scene has become a trope in itself over years, lampshaded, exaggerated, imitated, parodied, nearly qualified for being aDead Horse Trope, and yet it doesn't make any sense in context. Real police detectives are trained to be tough and hardened men with plenty of interrogation experience, and yet all of them seem stunned by a nearly-childish trick (though considering what kind of a person Catherine is and how the story shows that even the most hard-assed man can be swayed by a woman, this actually makes a lot of sense).
Evil Is Sexy: When it's played by Sharon Stone, anyway. Roxy also qualifies for this trope.
Hollywood Homely: Brown hair, brown eyes, glasses, sensible, drab-colored clothes (and presumably underwear as well) as supposedly enough to make Beth the plain alternative to the glamorous Catherine though she was still considered desirable enough to gain the sexual interest of Catherine and Nick, do a nice topless scene, possibly have made Catherine obsessed with her and possibly have seduced and killed Johnny Boz.
Unfortunate Implications: And how. As stated earlier, the many accusations of misogyny and homophobia—virtually every woman in the film is presented badly (even if she's innocent, Beth is at the very least, pitifully hung up on a guy who doesn't give a damn about her), and each of these women is either gay or bisexual.
The Untwist: Catherine was so obviously telegraphed as the killer that most viewers believed it when the evidence began pointing to Beth. The filmmakers stated they had to add the last shot probably revealing Catherine as the real killer specifically to lead people in the right direction.