People who are difficult to get along with are what I call "saint-makers." Whenever we're near them or even merely thinking about them, we cannot remain spiritually stagnant -- we either move forward in holiness or we sin. They give us ample opportunities to grow in patience, forgiveness, unconditional love, reliance on God, etc.
God allows us to be in hurtful relationships (*note: I said "allows" not "wants"), because he does not interfere with the free will of those who hurt us. But he does want good to come from the pain. To make that happen, he uses it to show us the limits of our love so that we can stretch and grow stronger in our ability to love unconditionally. (Dangerous abuse is a separate matter and should be fled or stopped immediately, for only then can growth resume and healing begin).
C.S. Lewis said: "To love at all is to be vulnerable. Love anything and your heart will certainly be wrung and probably be broken. If you want to make sure of keeping it intact, you must give your heart to no one, not even an animal. Wrap it carefully around with hobbies and little luxuries; avoid all entanglements; lock it up safe in the coffin or casket of your selfishness."
The hurts of love should never destroy us. God heals us as we forgive others.
Let me emphasize that God does not allow the troublemakers to go so far as to destroy us -- i.e., to destroy our faith, our lives, our dreams, our hearts -- when we keep turning to Jesus. This is what happened in today's first reading. God had allowed Assyria to advance upon Israel, because the Hebrews had turned away from his protection. But he would not allow Assyria to completely destroy Israel. They were stopped just before they reached Jerusalem, the heart of the nation's faith.
If someone is nasty and arrogant and unGodly toward you, like the Assyrian king was toward Israel, or if you've not been able to stop people from advancing against you, or if there seems to be no end in sight to a bad situation, remember that God will not let this go all the way to utter disaster. If you keep your eyes on Jesus and deal with the problems the way he wants you to, you will be protected and you will grow strong.
This truth is hidden from "the learned and the clever," as Jesus said in Today's Gospel reading. It's revealed to those who trust in God the way young children trust their parents.
Jesus said, "No one really knows the Father except the Son and all those to whom the Son reveals him." Has Jesus revealed the Father to you? If you're teachable, yes! Has Jesus made known the Father's unconditional love for you? Every day! As long as you stay close to Jesus, walking the path of holiness in his footsteps, your Daddy-God will not allow any person or any situation to hurt you so badly that it destroys you.