It happens in real life too* - all the time. A glance, a touch, and somehow, someway, the chemistry is there. It's love at first sight.
Then there is the "No, No, No, Yes", romance book, where hero and heroine hate each other on sight (but they manage to overcome that - usually by getting alone and naked together...) There is the man falls for woman and
There is the woman wants a man and goes overboard to get him... The Phallus from Dallas springs to mind, with Ciarra Sim's unforgettable character, Hannah, who tracks down her
There is the novel where the hero and heroine are kept apart by circumstances beyond their control - but they always get together in the end.
Love is complex. It's lightning fast, it grows slowly, it's incandescent, it's smoldering coals, it's fragile, it's incredibly strong. But it's not a formula. You can write a formula romance, but love is anything but predictable. So - when you read about a heroine falling instantly in love with a hero, or when you read about the couple who can't stop bickering until they realize they are actually in love... you just have to sigh and smile, and hopefully give a nice review on Amazon**.
*I met my husband at the polo club, and I knew right away he was "the one". I told my sister I'd marry him, when we'd barely spoken to each other. We met in 1979. We married, and are still together! Love at first sight!
**This whole article came about because someone accused my heroine of not being "reticent" enough towards my hero and shot my book down in flames. In other words, the heroine was infatuated at first sight with the hero and didn't resist. So, if you want a book where the couple hates each other on sight, won't speak to each other, or think the other character is an ass, jerk, etc., there is a wonderful book called "Pride and Prejudice" that I hold up as a shining example of how a romance book should be written when the two main characters are not smitten with each other. If, on the other hand, you enjoy a sizzling love story, but the two characters have to learn to trust each other, and have to overcome obstacles beyond their control to be together, you may like my Alexander series. It's up to you. But now, you've been warned.