I've noticed a few things:
1) I've been more aware of when I'm going to say something whiny or complain. And sometimes I decide to bite my tongue.
2) Sometimes it's worth taking a snap on the wrist when something really ticks you off and you say an occasional word you shouldn't say.
3) A wrist can stay red longer than you'd think. Hmmm. Who knew.
4) If you smile at people, they smile back. And it makes you happy.
Making a concerted effort to smile, be happy and positive, and refrain from complaining has been good for me. I definitely haven't been perfect (just ask any family member). But by golly, I have less red marks on my wrist than I did a week ago.