Found on Ask Reddit
1. They can accept when they are wrong about something without getting angry or defensive.
2. They do the right thing even when they think nobody is watching.
3. They make room for you in a circle of conversation you are hovering the outside of at a social gathering.
4. Those little casual acts of kindness that they do on automatic.
Holding a door for someone, helping someone if they drop something. Just a default attitude of pleasantness and support to everyone they meet.
5.If they are polite and pick up after themselves in public.
6. If somebody is getting talked over, they actively make sure the person gets to say what they wanted to say.
7. When they actually ask you followup questions when talking to you, rather than just switching straight to their own answer.
8. If you accidentally fart and they don’t make a big deal out of it.
9. They don’t somehow make every conversation about them.