The Gospel according to Luke (LK 9:1-6)
Jesus summoned the Twelve and gave them power and authority over all demons and to cure diseases, and he sent them to proclaim the Kingdom of God and to heal the sick. He said to them, "Take nothing for the journey, neither walking stick, nor sack, nor food, nor money, and let no one take a second tunic. Whatever house you enter, stay there and leave from there. And as for those who do not welcome you, when you leave that town, shake the dust from your feet in testimony against them." Then they set out and went from village to village proclaiming the Good News and curing diseases everywhere.
As you walk, your feet will collect a lot of dust whether you like it or not. It is what it is. So, there will be times when people are not welcoming towards you. It can be frustrating when you do your best to bring peace but your presence is just not welcomed. It may not be a great experience but it still is an experience. It's ok to get rejected, you will still gain something - even if it's just resilience training. By shaking the dust from your feet, you are also getting rid of unnecessary burden. You will also feel lighter. The peace you give out that got rejected will return to you if you let it.
Wouldn't you prefer to leave a place in a better state or at least how you found it? If you came in peace wouldn't you prefer to at least leave in peace.