Amphetamine, Methamphetamine, Caffiene, Ephedrine, Nicotine, Cocaine, <span>Methylenedioxymethamphetamine (MDMA or Ecstasy)</span>
A. Bartender would be talking with guests and in a parlor / bar.
The answer is:
Age
This is because if your young your organs are not as developed. When your older your body handles more because it is developed fully.