Having grown the Startup Grind community from 100 to 600 volunteer user groups around the world, personally interviewing thousands of people who wanted to lead, onboarding hundreds of leaders, managing over 5000 volunteers across 127 countries, and managing a global community of (then) over 2 million people - the thing that struck me the most was how no matter where people came from, where they lived, what languages they spoke, what their culture was - we felt like a family and stood by each other through good and bad times.
Because of this, I've learned that 99% of the time - people are good and want to do good.
the surprising part - is that I also realized that the more you control your members with rules and regulations, the more negative effect it has on your community. It's really important to have guidelines and terms of service etc - but being dogmatic about it (in most communities - there are expectations of course) - just loving and nurturing and working with your community - and leading the way as a great example - is what truly makes a community amazing. (read: lovingly enforce the rules - when absolutely needed - with justice and unbiased fairness)
I always believe that "generally - it starts at the top" - The energy you bring as a leader - is what gets filtered down (once again - this isn't always true for all communities!)