I have a question maybe a more experienced fan can answer. Early in the show we see a little jealousy in Penny with Leslie Winkle, But there is no Jealousy with Dr. Stephanie. Then after the break up we see it with Dr. Plimpton and Priya, but not the Donor. Why is that? Just curious.
I'm not sure if there is a definite answer to this. I'm assuming the leslie Winkle was season 2 (not 1). Part of that I think that was the episode after their real first date and Leslie was educated and she was not. Dr. Stephanie was a little later and I think Penny sort of moved on from Leonard at that point. I think Dr. Plimpton was like the second episode after they broke up in season 3. He was supposedly so devastated about breaking up with Penny but seem to move on quickly. It didn't help that she was beautiful too. Actually she started out okay with Leonard and Priya but Amy pointed out that she was beautiful and came from the country that was known for the karma sutra.That's when Penny started crying. The Donor Penny knew all about what was going on with trying to get money for the university. Not only that the woman was like 70 years old and how can you get jealous over that.