Here's a few messed up things that makes our hormones override our logic.
Similarities
Opposed the the cliché comment saying: Opposites attract,
Studies proved that right here in the real world where homo-sapiens apply this lovely practice of co-existence, that two individuals that share similar idiosyncrasies and dispositions tend to bond better. This often leads to them falling in love due to the fact that they bonded and could end up in probable bondage - or worse - marriage.
Looks of the Parent of the Opposite Sex
Research shows that similarity in eye color and hair is a strong attractive pull towards an individual especially if that resembles that of your opposite sex parent. they relate this to another first love. and if we find similarities in a possible partner... yup you guessed it LOGIC GETS LOST!
Personally i think it is rather due to the fact that rationally we look at the other persons parents thinking; is he/she going to end up looking like that? if the person of interest ends up looking like one of their parents, is that truly what I want to wake up to 30 years from now?
Size Matters
Psychological Reasons for Love – Height matters, being tall helps!
Yes, it does, unfortunately. Especially, when it’s the man! What girl would not like her head tucked under his chin or stretching on her toes for a kiss? Taller men do enjoy a certain level of advantage when dating.
Eye Contact
Some studies have shown that gazing into each other’s eyes for about two minutes can incorporate the feeling of attraction between them. I heard that any eye contact that lasts for more than six seconds means either and invitation for sex or the threat of murder... nuff said!
Odor
Ovulating females attracted to body smell of men with high testosterone levels. True story!
Call it insanity, hormonal flux or the lack of sinus canals - the experts call it truth. This does however explain why a courting male nine out of ten times USED TO OWN A HOODIE!
Warm up the date a little! 
Studies show ( I wonder if the people who took some much time studying these human dating rituals managed to make time to apply the knowledge, or at least go to the pet-store?)
As I was saying, studies show that the type of first date depicts a lot about the persons personality, and that a Coffee date implies a warm welcome nature, something that triggers a spark inducing the temporary urge to shack up.
The Nest
Sure experience mobility and other earthly possessions count. and being classy is mostly considered a perk.
Subconsciously though woman want to know that once they start procreating, that their young will have a safe comfortable and stable setting.
I suppose this makes sense in a way, if the mansion is in place and the partner proves unstable - there is medication for that.
And if the way too stable partner proves to mundane - There is Alcohol for that.
A dog as your companion.
Dog owners are more likely to be perceived as caring, relaxed and approachable ans also creates the illusion that the person is inclined to be more commitments orientated and nurturing.
Looks like I read the memo wrong; I just end up taking home dogs!
Showing some Pearly Whites
We all know that one can not fill from an empty cup. Subconsciously we are attracted to someone that depicts happiness, as we are after all looking to find our own happiness.
Step in Sync
Weird psychological reasons but a valid reason none the less.
We are actually attracted to synchronized actions, when our own actions and body language gets mirrored back to us, well maybe it just makes us feel as one in that moment, leaving us longing for more.