男女不可能就是普通朋友没有任何杂念，除非双方都很丑。不过从那个when harry met sally电影里的对白来看，就算丑也估计有杂念了，不敢承认罢了？

Harry: Because no man can be friends with a woman that he finds attractive. He always wants to have sex with her.

Sally: So you're saying that a man can be friends with a woman he finds unattractive?

Harry: No, you pretty much want to nail 'em too.