>But people lacking the same incentives will probably unknowingly slide into some form of bad behavior even if they've been active on the site for years - it will just happen naturally, because their economic equation is "amuse myself" with no mitigating factors. But most of the time it probably doesn't cause overt vandalism, just poor commenting hygiene.

I am not so sure about that - I come here and post comments in the hope that people will like them (doesn't work that well) because I derive my sense of worth from how much karma I have

Can't be the only one.