*Worry is pointless and detrimental to your health.*
There are two kinds of situations that call for worrying. The kind you can change and the kind you can't. If you find yourself in a worrisome situation that you can fix, then make a plan, take action, and allow yourself to stop worrying.
If on the other hand, the situation is completely out of your control, CHILL OUT! If there's nothing you can do, there's nothing you can do. Worrying about it will only do you harm. ((It has been proven that excessive worrying releases cortisol into your blood stream. This harmful chemical causes aging, cancer, high blood pressure, increased risk of heart attack, and reduces the efficiency of your immune system.))
*Anger is a useless emotion*
Anger is one of the most basic human emotions. It's hardwired into our brains by our biology. Fortunately for us, we have logic and reason on our side. Here's the thing. The world is full of lovely, kind, people who want nothing more than to sprinkle sunshine over the world. The world is also full of jack-holes who take pleasure in ruining your day. If they ruin your day, they win. Don't let them win.
Try to let rude, accusatory, self-entitled, and confrontational people pass into and out of your life without leaving negativity stains on your emotional carpet. Spray yourself down with mental scotch-guard. The best defense for this is pity. Horrible people have horrible lives. Maybe they have more money, better cars, a nicer house, a prettier wife, than you, but for some reason, they are unable to appreciate what they have. That is something to be pitied.
Another defense is thankfulness. Be grateful that you didn't accidentally marry someone that negative. ((unless you did, then I'm really sorry)) Be grateful that person's unhappiness isn't YOUR unhappiness.
Most of the time, the situations that anger us are not caused intentionally. They are caused by small, insensitive, and repeated slights from those we love. Instead of allowing these situations to cause familial discord, ignore them. Which will take you longer, fighting with your spouse about taking the garbage out, or taking it out yourself? I ask myself this. Would I rather have an evening full of yelling and hurtfulness, or a happy evening together? This works in reverse as well. If your spouse/roommate/parent asks you to do something that you don't really feel like doing, just get it done. It will make everyone happier in the long run.
Another option is to just let their chore go undone. Perhaps they'll get to it eventually. Let people work within their own time frames. They are your spouse, not your employee.
If someone hurts your feelings, try to remember, that they didn't do it intentionally. They probably didn't even realize they were being hurtful. Rather than take the offensive, consider first. Are you being reasonable? Are your hurt feelings really his/her fault or are you being oversensitive? Is it important enough to ruin the rest of your day over?
Sometimes it is their fault. Sometimes it is a big deal. Just remember, once people start yelling, they stop listening. Once the yelling starts, it becomes a contest, and everybody likes to win.