There are 2 poles. Each opposite. 1 positive, 1 negative. 1 uplifts your spirit, and 1 depresses you. 1 is joyful, the other is sad. The name of the 2 poles are : better and bitter.
When you are grateful for life, your view of everything is better. You appreciate, you enjoy. Gratitude improves your humanity. It makes you better.
The opposite of gratitude is to complaint. When we are negative, and always finding fault, we lose the joy of the moment. The bitterness of fault finding makes us sad. Complaint is sadness. It makes you bitter.
The choice is yours. You can get better or bitter.