It is not the man who has too little, but the man who craves more, that is poor.
– Seneca


Context
The quote is from Letter II of Seneca’s seminal work “Letters from a Stoic“.

Meaning
If you always want more, you will always found yourself in a psychological state of lack, even if you happen to be “wealthy”.
Who is poor really? Is it the man who has little and lives a simple life but is happy in his everyday life?
Who is rich really? Is it a millionaire living in his luxury apartment or mansion but devoid of any genuine joy and meaning in his life, is he still rich?