Obi-Wan using his saber in the cantina in ANH was a last resort. He did try to talk the guy down and even offered to buy him a drink. When he got a blaster pulled on him and saw his protege thrown across the room, it was self defense. You know, restraint, discretion. Being the last to strike in a fight. It makes the Jedi cool when they actually show some control over a situation and try their best to resolve conflicts through means other than overt combat, even if it's as simple as trying to talk to someone calmly. If need be they'll fight, but it's only when absolutely necessary.