From "My Fair Lady" Prof Higgins asks this musical question after Liza runs off.
A Hymn to Him Lyrics

HIGGINS
What in all of heaven could've promted her to go,
After such a triumph as the ball?
What could've depressed her;
What could've possessed her?
I cannot understand the wretch at all.

Women are irrational, that's all there is to that!
There heads are full of cotton, hay, and rags!
They're nothing but exasperating, irritating,
vacillating, calculating, agitating,
Maddening and infuriating hags!

[To Pickering]
Pickering, why can't a woman be more like a man?

PICKERING
Hmm?

HIGGINS
Yes...
Why can't a woman be more like a man?
Men are so honest, so thoroughly square;
Eternally noble, historic'ly fair;
Who, when you win, will always give your back a pat.
Well, why can't a woman be like that?
Why does ev'ryone do what the others do?
Can't a woman learn to use her head?
Why do they do ev'rything their mothers do?
Why don't they grow up- well, like their father instead?
Why can't a woman take after a man?
Men are so pleasant, so easy to please;
Whenever you are with them, you're always at ease.
Would you be slighted if I didn't speak for hours?

PICKERING
Of course not!
HIGGINS
Would you be livid if I had a drink or two?
PICKERING
Nonsense.
HIGGINS
Would you be wounded if I never sent you flowers?
PICKERING
Never.
HIGGINS
Well, why can't a woman be like you?
One man in a million may shout a bit.
Now and then there's one with slight defects;
One, perhaps, whose truthfulness you doubt a bit.
But by and large we are a marvelous sex!
Why can't a woman take after like a man?
Cause men are so friendly, good natured and kind.
A better companion you never will find.
If I were hours late for dinner, would you bellow?

PICKERING
Of course not!
HIGGINS
If I forgot your silly birthday, would you fuss?
PICKERING
Nonsense.
HIGGINS
Would you complain if I took out another fellow?
PICKERING
Never.
HIGGINS
Well, why can't a woman be like us?

[To Mrs. Pearce]

Mrs. Pearce, you're a woman...
Why can't a woman be more like a man?
Men are so decent, such regular chaps.
Ready to help you through any mishaps.
Ready to buck you up whenever you are glum.
Why can't a woman be a chum?
Why is thinking something women never do?
Why is logic never even tried?
Straight'ning up their hair is all they ever do.
Why don't they straighten up the mess that's inside?
Why can't a woman behave like a man?
If I was a woman who'd been to a ball,
Been hailed as a princess by one and by all;
Would I start weeping like a bathtub overflowing?
And carry on as if my home were in a tree?
Would I run off and never tell me where I'm going?
Why can't a woman be like me?