How much is "too much"?

[bcubed]

I'm not talking from the point of view of the medical community. I'm also not asking what's the minimum use to cause physical addiction.

I'm actually reminded of the George Carlin skit where everyone driving slower than him was an "idiot," and everyone driving faster, a "maniac." Sometimes the same thing seems to happen to drug use.

Nowadays, people are willing to admit that with, say, sex, "too much" is a vague term that has as much to do with one's own personal code as anything. Granted, a promiscious person may take more risks, but as long as one is aware of the risk, there is a fair amount of latitude about personal preference.

Does this apply to drugs? If a person is enjoying him/herself, does this mean use is not excessive, even if the risk of negative consequences is relatively high? Or does this give too much leeway to a user to "justify" her or his use?