This is something to keep in mind. When studying racism, I learned that it is defined as:
Racism=prejudice +power. We can also apply this to sexism.
Sexism=prejudice + power to act on that prejudice.
You will encounter women who have faced sexism and who misinterpret your intentions. Rather than dismissing their experience, it is more effective to prove them wrong through demonstration. It is important to feel at peace inside about those aspects of sexism we reject, but to also be honest and raw enough to admit where we are blind or dismissive.
[Edit] @Lateralus, I think I agree with you that it's a problem to focus on minutiae when there are bigger issues with sexism, and I don't think that women see every incident as equal. If a stranger made the comment to me that I'm too pretty to look sad, I could ignore it and feel uncomfortable, but I could also be aware of it as having some element of a positive motive.mMy bigger concern has to do with the reaction if I don't engage the stranger. If he were to walk away and call me a bitch then it would be threatening. I think it is good to note the minutiae, but thatnisn't the core concern that women have. A random comment that feels a bit sexist, but also like there was some good intention is not the central aspect of my own concern as a woman. My core concern is how sexism has influenced my career, my relationships, and my own assumptions and sense of self. The minutiae is also a problem especially in environments where it is repetitive, but I think women in general have a sense that there are different levels of sexism.