1. “If ‘someone’ doesn’t get along with others, who is responsible?”
Certainly not God. He has given us the perfect guide regarding how we are to treat one another in:
Fellowship relations, Colossians 3:12-17
Marriage relations, Colossians 3:18-19; Ephesians 5:25-32; 1Peter 3:1-12
Parent/Child relations, Colossians 3:20,21
Business relations, Colossians 3:22 – 4:1
Outside relations, Colossians 4:5,6

2. “If ‘someone’ doesn’t get along with others, who is responsible?”
It might be others through their attitudes and activities.
But:
God forewarned us about this, 1Peter 4:1-5
He also told us what to do about it, Matthew 7:12; Romans 12:14-21
So, either be more mindful of your associations, 2 Corinthians 6:14,15
Or, influence and/or convert them, Matthew 5:16; Acts 16:23-34

3. “If ‘someone’ doesn’t get along with others, who is responsible?”
It probably is ME! Am I being the kind of person who offers something besides selfishness and conceit to a relationship? Am I manifesting proper attitudes of genuine concern, compassion, loyalty, and trustworthiness that are essential to any lasting and mutually pleasing relationship?

4. “If ‘someone’ doesn’t get along with others, who is responsible?”
Proverbs 18:24: “A man who has friends must himself be friendly, but there is a friend who sticks closer than a brother.” Only I can control my attitude and conduct in a relationship. I can allow others to influence me, but only I can determine my disposition and input (action or reaction).

5. “If ‘someone’ doesn’t get along with others, who is responsible?”
It can’t be God, for He has given the information we need, 2 Peter 1:3
It might be others, but I can either change my associations, or I can change the associates.
It probably is me not being the kind of person God told me to be, or feeling and acting the way God told me to feel and act.
Two things are sure, I have to do the right things in all of my associations and relations, Matthew 5:44-48; and
Being the kind of friend to others that Jesus is to me the key, Philippians 2:1-8