Become gratitude and enjoy!
You have to just become gratitude! The best way to become gratitude is to learn to enjoy without a reason. Enjoy everything that you see, everything that you hear, and everything that you do, with the supreme confidence that Existence is taking care. Life will then simply transform in front of your eyes and you will be overflowing all the time because you are always enjoying it.
A small story:
There was a man who was walking past a mango grove, which was overflowing with mangoes of different varieties. He entered the grove, looked around, studied it, took down some statistics and left half an hour later, with facts and figures.
After a while, another man walked past the same grove. He entered it, plucked a few mangoes, ate them joyfully and left!
Now, please don't stop by at any mango grove and eat up the mangoes. You might get stoned for it! Try to understand what I am trying to say. Just learn to enjoy life without questioning, although I don't mean that you should drop all your work and only enjoy all the time.
You need to work, no doubt. No one is going to give you everything if you only enjoy. I am only saying, don't look for reasons to enjoy, that's all. Simply enjoy everything without questioning. Let enjoying become your very nature, then gratitude will become your very being.
Your profession may be anything, your social status may be anything, your economic status may be anything, but enjoying is something that every man can do irrespective of all this.
The problem is that you always feel that there should be a causative factor for everything including enjoyment. You have trained your mind with these kinds of thought patterns. This is also the reason why, you often feel, that others have been blessed with things that they don't deserve, while you have not been given enough for your efforts.
You always think that you need to work hard in order to enjoy. No! Working hard is alright, but it has nothing to do with the capacity to enjoy. Drop this idea. This is the only way you can stop complaining or feeling dissatisfied.
Existence showers. If you choose to enjoy it, you will. It is purely your choice. You choose wrongly and then complain or blame someone else. Remember, no one is responsible for anything that happens to you. Everything is a conscious choice that you make unconsciously. Because of lack of awareness in you, you make unconscious and monotonous decisions and land up complaining about life.
Always remember that heaven and hell are not geographical locations in the outside world. You create them within yourself. The moment you lose trust over Existence, you alienate yourself from it and carry hell with you wherever you go.
A teacher once asked her students, 'Can anyone tell me where you think hell is?' After a long silence, a girl stood up and replied, 'In my dad's study.' The teacher was surprised and asked her why she had said that. The child replied, 'Every time I go to my dad's study, he says, get the hell out of here!'