The title is taken from the opening line of the 1928 pop standard "Makin' Whoopee."
This was the final episode in the series. Two highly successful spin-off series, "Robin's Nest" and "George and Mildred" quickly followed .
The closing the credits of this final episode finish with the words THE END.
In the spin-off George and Mildred, curiously no reference appears to be made by George or Mildred, that their new neighbour looks exactly like one of their former tenants' older brother Norman. In fan theory, either George and Mildred weren't in close contact to Norman in this series, or they chose not to say anything in G&M as it "wasn't their business", in case it was some weird family history.