Almost nothing immunizes us from the every day frustrations more than a healthy sense of humor -- particularly the ability to laugh at ourselves. Every long-term relationship gets to a point where your spouse knows you almost as well as you know yourself. He or she will see your quirks, anticipate your unhealthy responses, and know the ways that you sometimes get in your own way. Even if you tried, it would be difficult to hide your true self from your partner.
If you are unable to laugh at yourself, you're in for a long, bumpy ride. You will struggle in your relationships because, as your spouse teases you, notices your flaws, and occasionally points them out, you will feel and probably act a bit defensive. This, in turn, will exacerbate and highlight your weaknesses, making them seem far more significant. What's more, your reactions to your spouse's comments will create additional issues for the two of you to deal with, and your "small stuff" will start to seem like big stuff.
If you look around at the happiest and most loving relationships, you'll almost always notice that both people have an ability to laugh at themselves. Both partners will have the perspecitve necessary to stay lighthearted as their own imperfections come to the surface. This creates an environment where occasional teasing or kidding around is okay, and where one feels safe in making observations or suggestions. Your relationship has the chance to deepen and grow because both parties feel safe.