Although it's corny, that's its charm and that's why 3rd Rock from the Sun will always be a classic of the 90s.
I watched Friends and Frasier then.
In British sitcoms, Only Fools and Horses just has this natural, almost kitchen sink drama quality in places, a sense of tragedy, that elevates it. Whatever Happened To The Likely Lads does too to some extent.
However - there were many great middle class sitcoms through the late 70s and 80s that would now be deemed old fashioned by many today (originally hit on the head by Keeping Up Appearances generally poking fun AT, rather than with, middle classness). Shelley, starring the recently late Hywel Bennett, was one I remember.