What is precious and horribly elusive to you may be attained or destroyed in the blink of an eye, hundreds of times a day, by someone else. The two of you aren't necessarily enemies but may see each other as alien, your conceptions of need borne of vastly different experiences of fulfilment and disappointment. Two such people meet in Michelangelo Antonioni's 1962 film L'Eclisse which taps an existential horror of nuclear war for a beautiful film about the limitations of love.
Vittoria (Monica Vitti) has left her fiance after finding herself dissatisfied with her feelings. After staying up all night with him discussing the breakup, she confirms to herself that she'd only been going through the motions and no longer loves him.
For the first portion of the film she wanders aimlessly, meeting her mother and her friends. At her friend's apartment she ponders pictures from an African vacation, images of values and customs remote to her, she can only guess at the level of significance they have for the people. Goofing off with her friends, she dances in black face, the activity superficially having no serious implications for them, but afterwards we see her watching other people, trying on modes of behaviour as though trying to study the ways in which feelings manifest. After a bad day at the stock market, she follows a man who lost millions. He doesn't seem to notice her, she watches him doodle some flowers on a napkin at a restaurant.
She becomes a rather profound avatar for the film's audience as we're compelled to think for a moment why we look for movies like this, what we're looking for.
At the stock market is a broker named Piero (Alain Delon), a handsome, constantly fast moving man, buying and selling all day. When Vittoria asks him if he hires call girls, he says, "Who has time for call girls? I'm the call girl." One senses he's not being quite honest--we see him flirting with other girls, he may not engage prostitutes but he's certainly not chaste as it seems he takes her question as wanting to ascertain. There is an element of truth in his response, though. He is constantly moving and he's constantly moving the valuable possessions of others, portions of companies for which he has no concrete idea of size and meaning. His car is stolen at one point and turns up in the lake with a dead man inside and all he can talk about is how difficult or easy it might be to clean and sell the car.
He can't understand why Vittoria is so slow to accept his advances. He persists so he probably really wants her but like everything else Vittoria now wants to study the process, she interrogates or quietly watches his every flirtation, as though trying to divine the secret of indescribable human chemistry. When they finally kiss, in a rather potent symbol for them both, it's with a glass between them.