Oddly an intriguing thread. I do think there are things that help and hurt, and that there are things that are very flexible or make no difference at all. I think everybody knows this (or disagrees with it) so let me embarrass myself by writing some done
*) Hire carefully. People who are drama prone are so due to personality much more than anything else I found, also hire people who match the attitude that your current group has. If you hire rough and boisterous folks into a bunch of more sensitively inclined folks, or the other way around, you just create a bad mix.
*) For new hirees advertise upfront what you are offering and what you expect. That doesn't stop all wrong people from applying but certainly helps and also helps later when things need to be clarified.
*) Setting expectations rather than having 25+ randomly pick some is good (more drama if people violate their own expectations), i.e. give direction.
*) At the same time listen. But don't be afraid to disagree.
*) Spread the load, a lot. Not only for yourself but also for other people. Even if someone is very eager, give them sensible amounts of admin. Lots of people will burn out if the load is too heavy.
*) Have complaints rarely or never go to you first. Have class representatives, or other dedicated officers handle this. People with people and mediation skills and a thick skin are good for this, but after 2 years of complaints anybody can wear out.
*) People leaving isn't a bad thing if things are more peaceful and more manageable after. It's bad if someone wore out who helped a lot. Even then you can hire new ones.
*) Trying to be fair and equal-handed is good.
*) Be honest even if it might appear unpopular. Sensible/mature people will respect dissenting honesty more than idle agreement.
*) Respect is independent of how tough or soft you are. Being tough or soft has nothing to do with having a spine and an independent opinion. Some people will disrespect you no matter what you say or do. Don't take it personally.
*) If you have folks who show continued disregard for others and do hurtful things intentionally or because of personal problems, let go of them. Especially if they show no recognition of the problem, and willingness to change, when addressed.
*) Don't let problems get bigger for you than they really are. Some problems need no other solution than a word of acknowledgment and letting them be history. Most problems either have a clear constructive path to address them (so do that) or are of this type.
*) Emphasize the fun or the solution not the problems. Look forward, don't linger on the past.
Or the short form would be "common sense" but I've seen a lot of common sense going out the window when the going gets rough.
As for friends leaving, well I understand that one. Had friends leave and had to leave friends.