No one who looks at another man’s possessions takes pleasure in his own: for this reason we grow angry even with the gods, because someone is in front of us, forgetting how many men are behind us and what a massive load of envy follows at the back of those who envy a few. But so arrogant are humans that, however much they have received, they take offence is they might have received more.

Seneca, ‘On Anger’