Can't believe I never saw this movie, but then again, it came out in 1972 when I was neck deep in political activism and a movie starring Ryan O'Neal would not have been calling to me, though I always dug Babra Streisand (who more or less started the trend of spelling your name in an untraditional but phonetic way)—or almost always—just for being the amazing musical innovator she was etc. and I always dug Peter Bogdonavich, who even when his movies didn't work they were such brave attempts to pay homage to the history of films (no coincidence his first and greatest was THE LAST PICTURE SHOW) you had to admire the attempt.
Anyway, I caught it tonight and was pleasantly surprised to find myself laughing out loud several times at the kind of slapstick humor that normally leaves me either cold or embarrassed for those performing it. Because WHAT'S UP DOC? is Bogdanovich's homage to the "screwball comedies" of the 1930s and '40s. And he manages to pull it off, while still making a film very much of its time (1972). All the performances, intentionally over the top, were delightful, including Madeline Kahn's debut and that of my late friend Stefan Gierasch.
If you've never seen it, do.