We had a barbarian. In 1e, barbarians are suppose to mistrust and/or despise magic. They get experience points for destroying magic items. In fact, the rules state that they aren't even suppose to associate with clerics until at least second level. Our barbarian didn't have any problem breaking magical items... but he also accepted magical healing and adventured with a cleric and a magic user.
Don't get me wrong - I'm not advocating that every fighter, paladin, or thief has to be exactly the same. But I think that, broadly, the class gives a range of behaviors in which a character's actions should fall.
Classes are set up with certain restrictions, negatives, and bonuses. When taken as a whole, these defining character class markers act as a signpost for how a particular class should be played. What's the point in taking a fighter if all you do is stand back and shoot arrows? Fighters are suppose to charge into combat - if you wanted to shoot arrows you should have made a ranger.
But what about beyond combat? Should character class dictate your character's out-of-combat actions? Once again, I say to a large extent, yes. A cleric should obviously gravitate toward serving the church. A cleric shouldn't be going down to the town market and try to lift coin purses.
Sure, some classes have more leeway than others. I think a fighter is about the most flexible character class. Every other class kind of pre-bundles a character profile in the DNA of the class's rules.
So to me, it's only good roleplaying to allow your character class (and race!) to restrict you when you're constructing your character's personality. After all, isn't that how it is in real life? We expect doctors and police officers to be trustworthy and car salesmen and lawyers to be silver tounged devils. Good roleplaying only reflects real life.