Different things to almost everybody.
We are all born with, and develop certain characteristics which makes up part of who we are.
These characteristics allow for the attraction in friendship and can vary widely, some may be seeking someone to confide in or feel secure around, while others may be looking for a mentor or a leader in the relationship.
In all cases, you are in the relationship because you are both seeking what you are looking for, and both have within you…the ability to make your friendship better
– Dr. Vik, The Culture King