Never underestimate your ability to get used to something and take it for granted.
It's astounding how much humans adapt to their circumstances.
Basically, everyone has a baseline that we'll call normal and that's how happy/sad/angry/frustrated you feel on average.
This baseline will look different for every person and is based on their life up to that point but the important thing is that everyone feels roughly the same at their baseline.
When something worse than your baseline happens you'll feel bad and when something better than your baseline happens you'll feel good.
Your baseline might be playing video games, browsing the internet, having nice food and a good home. Your good day then might be a night out with friends in town. On the same scale your good day seems so very privileged compared to a family dinner at McDonald's but the both of you felt equally good at the time.
It's important to remember we all live our own lives and we can't hold ourselves to the same standards as others for that reason. That's why we also shouldn't hold it against those who have more than us when they have a bad day just because you have it worse. For that person their bad day feels just as bad as your bad day does to you.
We should acknowledge the privileges we have and be thankful but also we can't beat ourselves up over it.