Gratitude is overrated and over-applied, and often prescribed disingenuously. Resentment, it's opposite, is poison in the modern world. Resentment is an impulse that amounts to a shallow middle finger, and if you try to use it for long-term motivation you become unstable. Many people turn to intentional gratitude as an antidote to resentment, but it's often an overcompensation.
Become too grateful and you deny the state of the world, your motivation shifts and you become an unwitting agent of the status quo. And maybe the status quo isn't all that bad, but it does prevent striving to make it better. Monks and Nuns of various religions are probably some of the most active practitioners of intentional gratitude. They also have minimal impact on improving peoples' quality of life.
No wonder corporations love prescribing it, corporations are ultimately authoritarian dictatorships and/or oligarchies. Gratitude nips any rebellion in the bud at the lowest possible cost. Why create a startup that out-competes an old, incompetent dinosaur of a business when you can spend those hours appreciating ice cream and the fact that you have a roof over your head, didn't die in a car crash that day, and don't suffer from any chronic diseases that don't usually hit your age demographic anyway?
So by all means, don't be resentful be content, but save your gratitude for improvements, strive to enact those improvements if you can. And don't be afraid to use negative emotion as a pointer for where to start.