Whether you're the Chosen One tasked with saving the world or a schmuck with a sword in a generic fantasy setting you'll usually end up on a hard road with little tying you down. The noble adventurer will face this adversity with stoic determination usually born of a pure heart and a tragic back story. Others take a less arduous option.
Murder Hobo refers to a play style in role playing games (pen and paper or video/computer games) where the players eschew any sort of actual characterization for just trying to get as much loot and XP as possible with little to no consideration for how their actions effect NPCs or the game world. Wandering from town to town killing every goblin, troll, and sufficiently ugly peasant they meet the murder hobos paint a gruesome path of destruction across the land. Diplomacy will fail because at the core of the murder hobo ethic is the the rejection of the social contract. All they care about is increasing their power and accruing more wealth much like the dragons they slay. Dungeon Masters have few options when dealing with murder hobos. Since the hobos see violence as the only solution to any and all problems any attempt to rein them in will end in either the party dying or the city guard becoming just more XP on the hobos rise to infamy. Faced with this DMs have to get creative and hope that they can get through to the players.
The problems outline above rarely affect the worlds of computer games. The computer can hardly get upset at you for stealing everything not nailed to the floor. As such one can usually be a complete bastard with few lasting consequences. That said, in my experience, RPGs are more fun when you actually have an idea for your character and play as such. Of course he or she could still be a homicidal vagrant anyway.
RUST IS FOR THE WEAK