Why do the average people hate the wealthy?

This might be a sensitive topic but I’ve been seeing an increase amount of hate towards people that are wealthy. I’ve tried to think the reasoning for this and I can’t think of the reason.

Not trying to become political but most of the people that hate wealthy people are liberals. They feel like every should be treated the same and have the same resources which doesn’t make sense. Most of the people that became successful went through unimaginable amount of stress, loneliness, work, and etc.

My grandfather started a company from the ground up and became an extremely successful person. He was arguably top 100 influential person in my country when he was alive. And now, i feel like my friends resents me because of my background? They tell me that no one in the world should have the money like that and just doesn’t like me for it which doesn’t make sense.