I started watching Mad About You when it first went into sydication back in '98. I noticed as I watched between the sydicated episodes and the new ones airing on NBC that Jamie was bossy, PMSing, and ordering Paul around all the time after Mabel was born. In the beginning Paul and Jamie were both a young neurotic newlyweds who were both very much in love with each other. The post Mabel episodes Jamie comes off very bitchy...sorry for that word but it fits and Paul a very weak gullible fool. I think Helen Hunt getting too big for her shoes was the problem. By this time she had starred in the successful Twister and nominated and eventually won for As Good As It Gets and though the show was soo beneath her. Paul Reiser wanted out of the show I heard but stuck around for 1 million a episode. Helen started directing episodes herself and unfunny episodes like "Mabel Crying" and "Sometimes I wish I wasn't a mother with responsiblities" episodes came out of left field and didnt fit the show. The show dipped in quality and went totally downhill when Lisa was phased out and the in-laws were part time regulars. Stick with the 92-96 episodes those were hilarious.

To be fair, the writers probably had more to do with that than Helen Hunt herself regardless of her real personality. :)