Human beings bond in a number of ways. We have all manner of instinctual drives inherited from our evolutionary past; we have needs (for intimacy, pleasure, friendship, affirmation and a thousand more besides) which we depend on other people to fulfill. We have hidden parts of ourselves which we project on others so that we can, in relationship with those others, work out our inner conflicts by proxy. We have our inner cravings for power or esteem or security which we imagine that others can satisfy for us.