Even the most cynical of us are suckers for the idea of love at first sight now and again.
But the reality is far from as poetic, as most of us know. A nifty video from TED has broken down the processes and calculations your brain and senses go through when weighing up whether someone will make a good partner.
If you don't want your romantic daydreams ruined, might be best to look away now.
1. The eyes have it
First up, fairly obviously, are your eyes: while visual beauty standards obviously vary, healthy shiny hair and smooth, scar-free skin are cues that tell our brain someone is reproductively fit.
When your eyes are happy, we instinctively move closer so the rest of our senses can investigate...
2. Next up it's the nose's turn
Your nose will pick up your intended's pheromones, which convey physical and genetic information about them. If a woman is ovulating, men may get a testosterone boost.
Women's noses pick up MHC molecules, which the body uses to fight disease.
3. Your sense of hearing determines attractiveness too
Women like low male voices with narrow formant spacing, and men prefer women with high-pitched, breathy voices with wide formant spacing.
4. And obviously, touch.
You can figure out that one.
The first kiss really is important, as it provides so many tactile and chemical cues about your new beau.
If it's a good kiss, your bloodstream gets flooded with norepinephrine which makes your heart beat faster, your pupils dilate, and release extra glucose for energy (weyhey).
Norepinephrine gives your body tunnel vision so it can focus on the important thing that's happening. It can mess with your perspective of time and even heighten memory.
So while it might not be your heart making any of these decisions - at least your whole body is playing matchmaker on your behalf.