Sharon Tate's greatest performance
Certainly, had she lived, she would have made a great comedienne: there are those who would say her performance as Freya Carlson in "The Wrecking Crew" (1969) opposite Dean Martin was her best performance, but I like to think this picture was -- essentially she was playing herself and was completely at ease (despite being pregnant at the time) -- also I think the cast adapted this same casual attitude and played along at the pitch she set -- her scenes with furniture remover Terry-Thomas are the best in the picture (he mentions these scenes in his own autobiography "Terry-Thomas Tells Tales") and Vittorio Gassman, while looking out for Sharon on the set during filming, certainly doesn't go too over the top in his scenes with her (well, practically EVERYBODY goes over the top in this movie, but only to get some laughs out of a pretty lukewarm script--it is the performances one remembers from this film. I think the producers saw "It's A Mad Mad Mad Mad World", thought this had basically the same premise and let everybody act if they were Ethel Merman or Milton Berle: not bad thinking, if handled skillfully--somebody tried the same routine 30 years later with "Rat Race": big cast,lost treasure,loud performances)
Also this was literally the end of the 60s (in more ways than one) and this movie is a bit of a time capsule, with scenes shot in Piccadilly Circus and Carnaby Street at the twilight of the 'swinging 60s' with one of the people who symbolised the era in this, her last movie.