I definitely agree with you. There were a lot, especially earlier on, that are just classics and I could watch over and over. Then there were a good number, when I was re-watching the show on Netflix recently, that I just couldn't wait for to be over, practically.
I think this is most series. Some episodes are great, while others, not so much. Even fantastic shows have had lunkers (even Breaking Bad when they were chasing a fly in the lab all episode).
My biggest problem with Raymond was that after a while, I think the writers determined that what people liked about the show was seeing everyone argue, and had every episode be all about that. They got really formulaic. Ray would say or do something, Debra would get mad at him about it, and then Frank, Marie, and Robert would all weigh in.