The exception that proves the rule is The Hobbit where a happy content person is uprooted from his comfortable life to go hunt a dragon. I'd like to duplicate the theme and have a peaceful cobbler get shanghaied into an adventuring troupe but I need to come up with a better explanation for why besides "a wizard did it" which when Tolkien wrote it was a revolutionary new concept.
I have also seen quite a few non tragic ones. - The Orc who just went to screw around and bash a few heads in. - The soldier who just, you know, did his job. - The cleric who was sent by her temple to recover a lost artefact, not knowing that it was linked to a great evil. - The Ranger who just lived in his woods, not giving a sh** until he met the rest of the group and decided to join them because the evil they talked about threatened his woods. All of them were nice characters btw. Man that was a cool campaign. Such a shame we could never finish it.