There is a paradox between Dr.Mann's Mann's past (what we hear from Brand and others) and what we see from him in the current time.
When copperCooper and others awakewake Dr.Mann Mann, thehis first reaction of him is crying hardto cry. He changed a lot and his beliefs changed also. Rather than saving humans and such great goals, he just wants to go back to earth.
He lost his hope totally and years of solitude made him a coward,coward; broken and hopeless. I think Dr.Mann Mann is a character to show how a human could be miserable, villainous, and selfish. The
The only thing he thinkthinks about is to comebackcome back to earth and he dontdoesn't accept any advice from anyone because in his belief the misson ismission has failed buteven though others want to continue the mission.