I dunno, I think the performance by the actress is very important, at least it's enjoyable to me to see that the girls are into it and are enjoying what they are doing and you can tell within a few minutes of watching a movie whether they like it or not.. I guess there may be some that are directed to act this way in the movies, particularly the younger looking ones like in MUM-268 that act like "omg what is this man doing to me".. but I dunno, I don't really enjoy that too much.. I can see why people would of course, girls acting like virgins and all innocent.. Plus it's a trope in JAV that girls hold themselves off from too much pleasure, by saying stop or playfully slapping the guy or holding up the stop sign with their hands, or covering up their pussies with their hands.. It's pretty endearing and I'm into that, and I guess that's why I like girls who are more emotive than drugged, time stop, or girls who are unenthusiastic..
On the opposite side, I like the the forced orgasm genre, or girls passed the point of pleasure or taking too much pleasure, like in some of the Black Baby movies where they use toys on a girl until they are broken.. but I have to be in a certain mood for that, but it's very hot..