Don't blame Don Murray, blame the director
There's a lot of people out there like me who thought Don Murray's character, the naive but very obnoxious and a$$hole character, 'Bo' Decker, completely ruined the movie. It's hard watching the movie at all with pushy, obnoxious, obstinate-stupid Bo in his over-the-top hillbilly, white-trash overacting. But please don't blame the actor, Don Murray. He was being paid to perform this role as stupid, hillbilly cowboy white-trash, wannabee rodeo-cowboy loser. Don Murray the actor was capable of so much more and I seriously feel that Don Murray was completely mismatched for this role, although I understand the director's intentions that Bo was really the subtle 'villain' of the movie but could not be portrayed as a thug, more of a handsome pushy bully type that young women know all too much about and too often fall for.
Like most viewers we want to jump up and applaud when the bus driver stands up for Marilyn Monroe (he was a metaphor for the decent American male standing up for the weak) and shows Bo Decker for what he really is, a stupid, overbearing bully who shoved his weight around and got his way, not so much by threats but by being so overbearing that he got his way. The bus driver surprises us at the end by showing he is a skilled, fist street fighter who puts Bo on his backside by a flurry of well-placed punches. The bus driver is shown to be a good guy and fair fighter by not taking advantage of the situation to inflict serious bodily injury on the defeated Bo. Once Bo is down on the ground, with a sore jaw and more humbled pride than really hurt, the bus driver leaves him. But Bo learned his lesson.