I was actually referring to all scripted TV shows in my post above. I have yet to see Dexter but it could be an exception to my "rule." Some shows do start out good and then end up, well, bad and/or horrible. i.e... the new "V" show.
I have found that it takes a while for the actors to "become" the character on the show. I think that's why some of the first few episodes may not seem that good. But as the season moves on the actors get into the character and I think that's when the shows start getting more enjoyable. Just my take on it.
Cheerios actually do get stale after a while.
Speaking of cereal going bad. When I was young my mom had bought a box of raisin bran. We opened it up and found maggots inside. I still can't eat raisin bran.
Be sure to let us know how your experiment turns out.