I think a lot of the responses ("kind", "doesn't gossip", and so on) are important characteristics in a good person, but I don't think that every "good person" I know is what I'd call a "functional, well adjusted adult", which is what the OP is asking about. I have known a few genuinely kind people who are train wrecks in important ways.

I'm not sure what the answer is, but I'd expect for a well adjusted, functional adult to ALSO be able to put together some semblance of an adult life. They should be able to create and maintain relationships, manage their bills, manage long and short term goals, they should be able to work through setbacks, and they shouldn't have Peter Pan syndrome, they should be able to make appointments and keep them. In other words, a functional, well adjusted adult actively builds and manages their life.

IME, when a person cannot really manage themselves, it points to emotional issues that might be brewing under the surface.

A functional, well-adjusted adult has their sh*t together.

They are HUMBLE.

Don’t look for subtle signs of class, subtle signs of well adjusted adults, or wonder if they are MC or UMC.

Another for, they don't gossip. And they have confidence, do their thing, and don't appear to worry what others think.

They are friends with people of different ses.

They don't make a huge deal out of little mishaps.

They show up on time and if they say that they're going to do something, you can count on them to do it.

Doesn't need constant attention and validation.

Willingness to accept responsibility and admit mistakes. Also, they don't drink too much or give their kids stupid names.

They don't frequent this odious site.

Ability to laugh at themselves

Not on facebook

Humility. Compassion. Acceptance. Hardworking but not self-sacrificing.

PP - also, I see a lot of functional, kind adult postings on DCUM, along with the 'typical' stuff. I have benefitted many times from the perspectives and experience shared here.

Love this thread. I'd add - awareness of and willingness to acknowledge their mistakes/faults. Not taking self too seriously. Standing up for self when reasonable. Generosity in whatever form (time, money, kindness, advice) is possible given life circumstances.