There are a lot of factors that goes in for a person to get attracted towards another of opposite sex.
While some might seem weird, but it is true; there are psychological reasons that matters a lot to make the two people of opposite sex click into a relationship status.
Here are few of them. Have a look at the list, you might agree.
Same pinch! The similarities in nature, taste, attitude, personality make you bond better. This makes both of you to understand each other easily. Similarities bring in a level of comfort while being with the partner.