Think of one of your favorite songs, the one with those lyrics that touch you in a way that feels like they are speaking directly into your heart. Would it hit as hard if you replaced the lines with ones from Old McDonald had a farm? I'm guessing not. Because words matter. It's how humans are programmed to communicate. To connect.
 

To say that words don't matter is short-sighted, and harmful. Would a religious person feel the same about prayer? What about an addict in recovery? Would you call your partner a worthless piece of shit every day, and expect them to be cool with it because "words don't matter" and you didn't really mean it, you just said it every day, for absolutely no reason. Chances are you'd both start to believe those words before you even realized it. What about when you were a child, getting reassurance from someone who cared about you, those words mattered, and in some of our cases, an absence of those words mattered. The things we say are important.

I have mixed feelings about the phrase "sticks and stones may break my bones, but words can never hurt me." While I believe children need that message, that initial introduction to a "fuck what they say" attitude. It's a useful tool like the tooth fairy - a white lie to make something traumatic and out of your control, seem less scary and awful, until you are prepared to deal with reality. And that is that words can and do hurt. 

The things you say to yourself and others have a literal effect on the brain and it's up to you to be aware of the messages you are sending. 

I understand that it's difficult and uncomfortable and that not getting instant gratification sucks, I really do. Nearly all change is hard, right? Starting a new workout routine, home improvement, or learning a new skill, but those things have pay-offs. just like changing the language you use when you talk to yourself or others will. 

Make it a game, and reward yourself when you challenge that negative self-talk or don't lash out at a stranger in traffic. We all learn differently, and there is no magic button to shift a habit you've likely always had. A great place to start is to just be patient with yourself. You don't always have to get it right, you just have to try.