Try writing a sitcom and I bet you'll find it impossible not to think of some part of a favourite sitcom when forming it. I don't think there are enough sitcom writers' interviews on this or other sites, but then writers are notoriously shy about stating influences and alas are often just tossers.
So without their telling us, I'd be vaguely interested to know what other sitcom fans here think are sitcoms with some glimmer of connection in whatever way. There are some obvious blatant rip off ones like Chalk - Fawlty Towers and Miranda - Everything Else, but I'd like to know of less obvious examples, and I'll allow American sitcoms as I don't watch them much and have a feeling some of our new ones may be influenced by the Type of US sitcom I don't watch.
I've found OFAH to be Steptoe & Son like in the Rodney-Derek relationship, and The Big Bang Theory to be Red Dwarfish in the Sheldon/Rimmer v the others axis. Coincidence or influence? I go for the latter personally.
Note to Ed. This may belong in the writing section, if you want to move it, forgot it was there again.