One show that through it's run was consistently funny. There were very few episodes that I couldn't sit through again.
It's one of those shows that's comedy doesn't get dated. Plus the idea that they are writers for a comedy show is quite original (for 1961).
Also, the best thing that they did, that very few shows work with is the use of flashbacks without using previous episodes. (ex: the birth of Richie and the purchasing of their home when Laura was expecting.)
Flashbacks, to me, are a weak attempt for a series to use an episode as a filler.
With this show, it was used to show the Petries before 1961.