We are all fallible and subject to stress and frustration. However, if your primary goal is to put more and more people in touch with Jesus, you cannot afford to let turf-ism get in the way. You will have to struggle to find ways to overcome your own natural defensiveness and that of those you work with. By practicing these more open behaviors, you will likely get hurt. Someone else may not play by the same rules and may continue to make assumptions about you and refuse to cooperate with you.
Every situation is different, but the general rule of thumb has to be go back and try again.
When you think you cannot try any more, pray. What you cannot do, God can. My final suggestion is to pick your battles. Sometimes people can get into turf wars over insignificant issues. If you get stuck, ask yourself how important the issue is to you.