People may feel a positive kinship with another person-regardless of their gender-because they have similar interests and they are
on the same wavelength or compatable wavelengths in their approach to the world.

Then again, for those people who accept reincarnation [like I do]
two people may quickly grow close to each other because [though they don't consciously recall it] their souls remember that they had close, positive relationships with each other in past lives.