I have thought of it as one of my favourites but it's been a long time since I last saw it so when I watch it again I'll have to look out for "the blatant sexism" (but I guess those were the times). Yes, I think it's easy to 'park' all of that as from another time but sometimes it can jar.

“She wants me to tell her what to do with her third act.”
“Yes, tell her what to do with her third act!”
"In Niven’s case, there was a reason for his aloof behavior; during filming, he had separated from his wife, Hjordis, an event that caused the actor considerable anguish. Richard Haydn, who played a supporting role in Please Don’t Eat the Daisies, recalled, in The Other Side of the Moon: The Life of David Niven by Sheridan Morley. “A rather distraught David on the set. It so happened that we were both called for the first day of shooting but he was terribly nervous and that whole day’s work had to be done again later”.
Producer Joe Pasternak, who had worked with Niven twice before, was now observing a markedly insecure man, and devised a way to deal with his growing self-doubt. In Morley’s aforementioned biography, Pasternak recalled that “David used to keep asking me why I’d hired him when there were so many better actors around so I said, ‘Look, I’ll tell you what I’ll do. Every day I have to look at the rushes, and if you’re any good I’ll give you a quarter.’ So every morning he used to hang around like a schoolboy waiting for his 25 cents and some days I wouldn’t give it to him and then he’d act a bit better the next day. But I don’t think he was very happy…and David seemed much more turned in on himself than he had been before”.
This image of Niven is so vastly different from the dashing figure he cut in such films as Raffles (1940) – as an elegant jewel thief – and Around the World in Eighty Days (1956), where he played sophisticated world traveler Phileas Fogg. David reconciled with his wife before filming wrapped on Daisies, but the strain the incident had placed on Niven was glaringly evident to both cast and crew.” – Eleanor Quin, TCM.
Read More: https://www.dorisday.net/please-dont-eat-the-daisies/