yes, Understanding, Acceptance, Trust, Respect, and Appreciation. Those key five things. What each person expects, desires, earns, wants and needs most deeply. That, being the case, then close friendship and sometimes even love.
(2012: above, my longest, true, close Winnipeg friend of 65 years–Hugh, at the 100th anniversary of the school we attended together in grade 1, 1955; we’ve long shared and experienced the Big Five)