James 3:10-11–From the same mouth come blessing and cursing. My brothers, these things ought not to be so. 11 Does a spring pour forth from the same opening both fresh and salt water? 
One sign that I know I am struggling in my faith is how negative I speak about things.  Most of the time it is not audible, though at times alone it can be.  But during those times I realize that my heart is not filled with blessings but curses, not faith but unbelief!  Though God mercifully gives me grace to recognize it, repent, and get back on track, it helps me realize how crucial it is to live by faith, that our mind and speech follow…
What is clear from the passage in James is the impossibility of being full of both blessings and curses, that they can’t both come out from the same heart!  Which is why the best way to avoid being “fake” is to pray at all times like Paul says (Ephesians 6:18).  So even when we are struggling and don’t feel like being joyful, God gives grace to walk in love despite how we feel.  So that when we walk in faith, we talk from a place of blessings that is genuine, not being fake with a heart full of curses! (Psalm 10:7)
Though some people don’t worry about being “fake”, they just unleash a heart full of curses every where they go, giving people reason to stay away from them!  But we who profess faith in Christ, bitterness towards anyone with negative speech, shows that we have a heart of bitterness, proven by our speech (Matthew 12:34)!  So we should be honest with ourselves before God, and not deny the truth of our bitterness (James 3:14).
Without truly walking with Christ, it can take real painful work to be delightful and polite in our places of work among relative strangers.  So when we get around our families and people we are familiar with, we don’t work so hard at being phony, we just let all our bitterness out on the people we should be delightful to!
The beauty of a relationship with Christ is that He can unite our heart and mouth to love, peace, patience, etc. if we are truly intimate with Him (Psalm 86:11).  Like I’ve noticed in my own life, when negativity begins to try and take over our heart, we have to fight for it not to take over our mouth, for Christ sake and those He sends us to!
In His Love, Ld