To do things for others without the need of receiving "thanks" should be enough for a person to know that they are being humble.<quoted text>Jesus used even other words, "Let not thy right hand know what thy left hand is doing." (Leastways I think he was talking about charity works;)
One does not need "thanks", if they can walk away from a good act and feel good about what they just did.
This "self-fulfillment" can be enough to satisfy the person.
If it doesn't, then that person has not followed Jesus' teachings.
"To know yourself is to know the kingdom of God." - Jesus