Date change
Originally, this movie was supposed to take place in the then-near future of 1972. Immediately following the opening credits, there was a shot of a sign saying "Let Us Plan Your 1972 Holidays." At some point, presumably for the home video release, a new shot was edited in with the date on the sign changed to 2013. (Note that the location and the costumes look completely different from the scene that follows.)
Everybody knows the picture was made in 1967, so why "update" the time frame? It just seems stupid.
"All the universe or nothingness. Which shall it be, Passworthy? Which shall it be?"