That's what some who teach about gratitude say. Me, I disagree.
Oh, making a list every day is a very helpful tool for increasing awareness about how much you have to be grateful for. But that's all it is, in my opinion: A tool.
The goal is not to make lists, but to be be naturally grateful without thinking.
I have observed people who are struggling. They write a list all right - a list of all their troubles. Then they end it with a list of things to be grateful for, as if the two cancel each other out.
Or: They write their lists to in order to make deals with higher powers: If I am grateful, then the Universe will take my problems away, seems to be the attitude then. Some people's gratitude lists or blog posts read rather like the bargaining some people do with God or children do with Santa Claus: "I'll be good and grateful, if you'll only..."
The thing is, gratitude is attitude, nothing else. No behavior, no deal, no give and take (!). Attitude is a habitual and often unconscious way of thinking. If I am to describe what the attitude of gratitude feels like, then I would say it most closely resembles living in the now. I find that when I am filled with gratitude over noticing a pretty flower, I am in the moment, in the now. I stand still and listen to a bird singing, and find myself thanking the bird (although I know he's just hoping some (other) female will show up). I'm really thanking the moment and my own good sense to allow myself to have it. Appreciation is gratitude.
Why stop to smell the roses? Because we consider roses pretty? Because they do smell good? Or because paying attention, allowing yourself to use your senses makes you feel more whole, more alive? I'd say that last one is it. It helps you live in the now. And gratitude adds to that feeling.
So why not make a list? It depends on why you make the list. Some people start keeping gratitude journals because they are trying to change their lives. They want to increase prosperity or abundance in their lives, or they want to complain less. Gratitude is part of abundance, and it is counting your blessings, so they try to increase their thankfulness. And one way to focus on things to give thanks for is to write them down.
However, all too often, writing gratitude lists or focusing on giving thanks accidentally focuses on the opposite. I'll let Eric Butterworth in his book "Spiritual Economics - the prosperity process" explain:
Some persons, realizing the importance of the grateful heart, begin looking for things for which to give thanks. However, they mistakenly start with the perspective of inadequacy and insufficiency, and thus they simply become more conscious of limitations. The result is, instead of counting their blessings, they count their envies: "He is so talented"; "She has so many lovely things"; or "I wish I had a lovely home like they have." As a result of this very subtle process, they develop, paradoxically, "ungrateful hearts".
I write no lists. I have come across books that encourage such things, but I never found them interesting or useful. And, ironically, I find blogs that function as gratitude journals boring to read - probably because they are just an elaborate list.
This blog post is the result of me questioning my apparent lack of thankfulness since I don't write lists, nor do I end my day by meditating over all the good things that have happened or by visioning tomorrow's blessings. And yet I have a good life, few worries, and the sense to appreciate the good in my life and around me any time of day. So I wondered what was the difference between me and the list-makers.
My answer is in the approach and the mentality behind it. In my experience, gratitude is very similar to living in the moment, which means being able to enjoy the here and now and appreciate it. True gratitude is not about lists or even about being good. True gratitude is about perspective. It's about understanding what is important in life, in your life. It's about the big picture. Details to be happy about should function as reminders of that fact, not as a goal in themselves. Let me quote Eric Butterworth again:
[I]t doesn't make any difference to God whether you thank Him or not. But it makes a lot of difference to you. … [G]ratitude is not for God. You are not obligated to thank God for your life, for your job, for your prosperity. However, giving thanks is an important state of your consciousness which keeps you in an awareness of oneness with divine flow. When you understand this you see that a grateful heart does not need something to be grateful for. One can be grateful with the same spontaneity as being happy. It simply flows forth from within and becomes a causative energy."
Butterworth then goes on to explain a statement of Paul's: "In all things give thanks." [Corinth. 12:1) However, Paul doesn't say "For all things give thanks", Butterworth points out. That wording would mean being grateful for everything, including your problems. Again, it's not about making a list; it's about attitude:
What Paul does say is "in all things give thanks." In other words, despite the problems of lack, or even because of them, the need is to get yourself recentered in the awareness of the ever-presence of substance [i.e. abundance]. And the most effective way to accomplish this is by thanksgiving. He is stressing the importance of the grateful heart, not simply an expression of gratiude for things, but a heart that is grateful (full of greatness)."
The heart that is grateful runs on automatic, pulling in more good feelings and therefore more good without a second thought on your part. It's far better than a list!
 1 Thessalonians 5:18