It is so hard to keep my mouth shut. I struggle with it almost all the time.
When I am at work, I am gossiping or complaining about something far more often than I would like. The environment encourages it and if I am not constantly on guard I get caught up in it. It is especially bad if I am having a bad day.
When I am at home, it is a bit better as long as my wife and I are getting along. If we aren't, then it is a constant fight to keep the things that are going through my head from coming out of my mouth. Occasionally, I lose. I don't really mean them, I just get riled up and come up with the worst things.
The Bible isn't kidding when it says that the tongue is a restless evil. I realize that all these thoughts occur in my brain or mind, but as long as they stay up there then i have the chance to work through them and repent on my own. Once my tongue blurts them out, I enter into a whole new realm.
I believe that I have gotten better at controlling my tongue over the years, but I still struggle with it. I get frustrated that I think of these things at all. I cringe whenever something horrible moves through my head and presses against my teeth. I usually am able to keep it from escaping, but it is somewhat discouraging that my brain even creates them.
Luckily, sanctification is a progression. It is a slow process that doesn't end until we are all dead; the trick is learning to be thankful for even the tiniest bit of progress. Every little victory is Jesus working in our lives. They are all small proofs of the Spirit moving through us and methodically destroying the places sin had a hold on us. And that frees our tongues for far better endeavors, like worship.