What's so wonderful about the seinfeld show is it's a show that's relates to everyday activity in a humorous sense. Jerry is so brilliant in making everyday life seen so funny. I can watch the same show over and over again and yet, it's as good as watching it for the first time. What makes Jerry so good is his personality and way he comes across in all situations. Kramer, Elaine and George are also splendid as actors.
Another thing I notice is that each sub-plot within the show connects with one another. The show in entirely blends together. For example, in the truth episode, at different points in the show, everyone is specifying or telling the truth. Another episode is the mentor, where Jerry, George and Elaine all become mentors at one point or another (that's gold Jerry, that's really gold)