Anger has a lot to do with feeling that you're not getting what you want (or what you feel entitled to). You're not getting recognition at work or making the money you feel you should. Your kids don't show you the respect you feel entitled to as a parent. Your dog doesn't come when you call him. So you get mad.
Gratitude, on the other hand, has to do with being thankful for what has already been given to you. See this example:
Some years ago, when Dr. Gentry reported he had been trying really hard to overcome a major episode of depression (accompanied by lots of anger), he decided one morning to no longer ask God for anything for himself. He continued to ask God to watch over his children as they learned from their successes and failures, over his wife (the love of his life), over his brothers and their families, over his friends, over his clients, and even over his Bassett hounds.
But he figured that God had already given him more than he ever expected in life. His thinking was that if God wanted to bless him with more good things in the years he had left, okay. And if not, that's okay, too. Either way, he felt grateful — and, rarely got angry after that.
Start each day with a prayer of gratitude. Make a mental list of all your blessings — people, events, whatever — and recite them to yourself (silently or out loud) so that you remember the good things that have been bestowed on you and you are, indeed, thankful. And then see if you don't feel a sense of inner peace as you take on the challenges of the day.
Being grateful has benefits. People who appreciate the blessings of life find life to be more satisfying. Overall, those who express gratitude have fewer physical complaints, sleep better, feel more connected, and generally express more optimism than people who don't express gratitude.
You can feel grateful about big stuff and even really small stuff. Whether you win a million-dollar lottery, fall in love, catch a subway just in time, or find a great parking spot — all these types of events provide you with an opportunity to experience and feel grateful. What matters the most is acquiring the gratitude habit.