Come on. Even finding a definition of sexual harassment which people can agree on is notoriously difficult. Add to that the fact our society continues to push the idea that the men which women 'really want' are aggressive in initiating sexual situations. A man who does something as timid as asking whether he may kiss a girl can assure himself of inadequacy. (Not that there aren't plenty of exceptions to our media supporting this idea—but it's still implied pervasively. And some of it probably is just human nature.)

That said, even if it's not clear exactly where the line is—it's pretty easy to see that certain actions would be far across it, and that's largely what's come up in recent allegations. Though I don't think all of them have been super clear cut. 'Simple' is too strong here.