It sounds like a bit of a "bad habit"? Maybe you can make a "game" out of it and pay your children (if they're old enough) a quarter everytime they catch you saying something negative and also "correct" the negative immediately with a positive? My stepmother made my brother pay a quarter everytime he forgot to put his napkin in his lap at dinner . . .Or, kiss your wife everytime she catches you :-) If you do something "fun" like that it will take away some of your negative feeling for yourself. I find laughter or fun a good helper. Treat it like a video game where you're shooting at the negative comments. Eventually you'll get to seeing them "faster" so you can stop them before they come out of your mouth and/or start thinking other, more positive thoughts instead.