Bitterness and Pride
When you distance yourself from others, especially those you care most deeply about, you become bitter. You become bitter that they don't involve you in their lives and pin the blame on them, when really you know it's your own fault but your pride is getting in the way.
When you are bitter, you hold grudges. And holding grudges automatically cancels out the option of forgiveness.
It's easier to never get stuck in this rut than to have to get out of it. Having an unforgiving heart, pride, bitterness, and hatred ruins your life. It drags out the pain. It withdraws happiness you get from fellowship with others. It kills your relationships.
We need other people to thrive, even if we are naturally introverted. God put something in us that makes us yearn for interaction. When we cut that off, we cut off a part of ourselves.
So how do you destroy this problem right away? You must act right away. Learn to admit you are wrong. Learn to say you're sorry. Learn to humble yourself so you are completely vulnerable to others. Learn to let go of past disagreements. Learn to see the other side and see from more than one perspective. Learn to show your love for someone.
If you sense that you're cutting yourself off from people, jump back in and get involved. Don't fall into the rut. The rut is engulfing and many who fall in never come out.
But some do. How do they do it? They finally realize that they were wrong and have to do something to make amends. They love their loved ones enough to abandon their pride. They learn to trust in God's love.