Yeah, yesterday I saw one particular episode where I do think Judy was just awful. It's actually the only episode where I thought she was not funny, only mean.
When she hires Monica to make some dinner for her and her party or whatever, and she had the lasagnas on the freezer.
And the worst part for me was that she was actually enjoying it. I mean, she bet with Jack that Monica was going to screw something up! And when Monica told her about the fingernail on the food, she just laughed! :S
By the way, I do not think that Jack loved Monica less, only Judy. Jack seemed to have more faith in Monica than Judy. I think that Jack only wasn't aware that Monica felt that way (he didn't seem to be the perceptive kinda person).