If you have trouble appreciating an experience as positive, try to find another thing you were happy about before, and you might find that relativity between the two helps gratitude emerge that much more easily. It will help your life to spiral upwards, instead of pulling you down into the spiralling pessimism.
And the spiraling is not linear. It is exponential, and the developments of the last 1000 years will be made to look like nothing compared to what will happen in the next five thousand days. It might even happen sooner, as multiple S curves are right now stacking up to make production cheaper, human work totally overhauled, and the purpose of life re-evaluated for everyone on the surface of the world.