4. George McFly (Back To The Future Films)
George McFly, Father of Marty, was a complete and utter wimp. From his school days up until his adult years, he was bullied and bossed around by Biff Tannen without standing up to him. That is until Marty travelled back in time in Doc Brown's flux capacitor-powered DeLorean. After initially inadvertently coming between his own Mother and Father's potential relationship, Marty is forced to fix it in order to save his own life. But when the Biff of the 1950s is trying to get close to his Mother, Lorraine, George is forced to take matters in to his own hands. George plucks up the courage to floor the much larger school bully with a single punch, proving that he's not the wimp he appears to be, and changes the future so that Biff is scared of him - and indeed willingly works for him as a timid, hard-working suck-up.