I remember when it all started, and it was clearly remarked that it was a Sci-fi not to be taken seriously. The fact there are so many plotholes (there IS only one plot, Lister is the only human alive and he wants to go home) etc shows this. The fact that Grant and Naylor didnt give so much a thought to end of season to new season crossovers. Its no more serious than the I.T. Crowd or 2 pints and a packet of crisps. Its a 1980's/90's sitcom, no more no less and I love it for it!