Remember, when on a bike no matter if you want to be or not, you are an ambassador for the sport. The motorist who was behind you on the way to work when you ran that stop sign, now has negative feelings about cyclists. That hiker you blew off the single track, is now deeply resending mountain bikers...
When in traffic, if a car stops to let you turn, give them a thank you wave. Even if by law they were supposed to stop, it makes them feel appreciated. The leave the encounter with less negative thoughts about all cyclists.
When you come across hikers on a single track, give them the trail and say hello. Would you rather the hikers leave thinking "Those were some nice mountain bikers" or "Those damn mountain bikers are ruining the trail, who do I call to get them banned?"
The world doesn't need to be us vs them. A little bit of friendliness goes a long way.