Last night we ran a networking event in which people practiced being in agreement on multiple levels. There was a lot of laughter. People who normally dread speaking found themselves having a really good time. They discovered that interactions based on agreement are naturally energizing. Within an event, everyone wants to play.
The secret to agreement is that most people want to play. Almost everyone you meet will be more comfortable when connected and will be willing to stay connected given the opportunity to connect without violating their outcomes, beliefs or values. Almost everyone is willing to find common ground.
A few people will want you to do all the work. They will tolerate interchanges only as long as they do not have to make any effort to find common ground. They will let you know that your agreement can never be precise enough to meet their criteria. They are in hiding - from you, and probably from themselves.
Outside the training room, just one person can make agreement work for a time. It's possible to connect with someone else's experience even when they are unwilling or unable to connect with yours. You have probably had those kind of connections: connections where the other person refuses to play. You agree, and they take. There is nothing that is so small that it cannot furnish a chance for such people to disconnect and disagree.
There are lots of ways to invite people into agreement and connection. Practice them continuously. Refine your ability to connect. Then understand that what you learn from some people is how to disconnect - how to form an agreement with their model of the world, and then gently step away from it.