Unfortunately, ungratefulness is a very subjective thing I don't really understand the meaning. When people don't own something and you have much of it yet you don't really like them and you want more that you think could fit your need and taste better, those people think you are ungrateful. While for you, having much doesn't mean you're happy and so as long as you're still able, you'll chase more. Things always have two sides.
You try to find excuses. You know it's true but you deny the truth. You look back and be pissed. You look forward but you're hurt. People don't know this. All they know is you already own something they don't have, which would make them happy if they had any, but you don't really like them. You want to get what makes you happy, which means would make you have more. This is what they call ungrateful. Why is that? You want things that can make you happy, they want things that can make them happy, that's the same thing. The only difference is the object. So what's ungrateful now?