The feeling of closeness, camaraderie, friendship with like minded people you could trust.
Haven't experienced it since I left.
Well I don't know what exactly you mean by people you can trust. Trust not to steal? Trust not to molest your kids? My brother in law stole from his employer and got removed as an elder. He moved away so he could get reinstated, which happened in no time of course. Child abuse, no further need to enlarge on that problem.
I think we all let people down sometimes by not being what they want us to be, I know I have. But in times of great need I have found people who care and who have helped me. They have kept me sane, no exaggeration. Some are atheists, some are religious.
As for friendship and social needs two Hindu ladies at work gave me lovely small presents at Xmas. We all went out for a colleague's sixtieth birthday a few weeks ago. It was spontaneous and informal and I had a great time. I've joined a pub quiz group through meetup and it's fascinating getting used to all the new personalities. I still have a friend I worked with thirteen years ago and a lady l met when volunteering four years ago.
I trust people as a group to help and support me when at work because my experience has taught me that as a team they usually do although individuals sometimes can get on my nerves. The key thing is they don't care what I believe or whether I attend a church or not. Just don't look for perfection anywhere. Perfect people are a myth as are tame lions on your lawn.