An iconic milestone for sitcoms I believe. This is one show, one show where I still have yet to tire of the repeats. It just has that relatable, urban contemporary pull (I'm from New York myself so).
There are 4 basic characters and interestingly they're usually more portrayed as inner city antagonism (especially George) instead of what typical comes to typical. Subjects about everyday life and dating without marital bonding (aside from one occasion that George wanted to escape from, ending in a moment where black comedy is at its blackest in sitcoms).
I think what amazes me about most every episode of this show are the multiple story arcs (usually 3) integrated in and with the cause, there's also some effect that returns with a punch, crossing over the other story-arcs. That to me is clever, clever story-writing and this is one of two shows where I might never get tired of seeing over and over.